he mere belief that you are receiving an effective treatment for pain can reduce the pain you actually feel. Researchers tested this placebo effect on 37 volunteers. Each volunteer was put inside a magnetic resonance imaging​ (MRI) machine for two consecutive sessions. During the first​ session, electric shocks were applied to their arms and the blood oxygen​ level-dependent (BOLD) signal was recorded during pain. The second session was the same as the​ first, but prior to applying the electric​ shocks, the researchers smeared a cream on the​ volunteer's arms. The volunteers were informed that the cream would block the pain​ when, in​ fact, it was just a regular skin lotion​ (i.e., a​ placebo). Note that each participant is contributing a pair of data: one measurement in the first session, and one measurement in the second session. From the 37 participants, the mean and standard deviation of differences in BOLD measurements are calculated. If the placebo is effective in reducing the pain​ experience, the BOLD measurements should be​ higher, on​ average, in the first MRI session than in the second. Is there evidence to confirm that the placebo is effective? That is, that the mean BOLD measurements are higher in the first session than the second? Test at LaTeX: \alphaα=.05.

Answers

Answer 1
Final answer:

The researchers conducted an experiment to test the effectiveness of a placebo in reducing pain. A statistical test called the paired t-test can be used to analyze the data and determine if the mean BOLD measurements are higher in the first session than in the second. The results of this test will provide evidence to confirm or refute the effectiveness of the placebo.

Explanation:

The researchers conducted an experiment to test the effectiveness of a placebo in reducing pain. They measured the blood oxygen level-dependent (BOLD) signal during two consecutive sessions with electric shocks applied to the volunteers' arms. In the second session, a cream that was actually a placebo was applied to the volunteers. The mean and standard deviation of the differences in BOLD measurements were calculated to determine if there was evidence to confirm that the placebo was effective.

To test if the mean BOLD measurements were higher in the first session than in the second, a statistical test can be used. The paired t-test is suitable for this scenario, as it compares the means of two related samples. The t-test calculates a t-value which can be compared to a critical value to determine if there is evidence of a significant difference. In this case, with a significance level of α = 0.05, if the t-value is greater than the critical value, it would indicate evidence that the mean BOLD measurements are higher in the first session than the second.

If the calculated t-value is greater than the critical value, there is evidence to confirm that the placebo is effective in reducing pain. Conversely, if the calculated t-value is not greater than the critical value, there is not enough evidence to confirm that the placebo is effective. It is important to note that statistical significance does not necessarily imply practical significance, so further investigation may be required to understand the magnitude of the effect.

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Related Questions

A particle moves according to a law of motion s = f(t), 0 ≤ t ≤ 6, where t is measured in seconds and s in feet. f(t) = cos(πt/3) (a) Find the velocity at time t (in ft/s). v(t) = (b) What is the velocity after 2 s? (Round your answer to two decimal places.) v(2) = ft/s

Answers

Answer:

[tex](a)v(t)=-\frac{\pi }{3}sin(\frac{\pi t}{3})[/tex]

(b)-0.91 ft/s

Step-by-step explanation:

Given the position function  s = f(t) where f(t) = cos(πt/3), 0 ≤ t ≤ 6

(a)The velocity at time t in ft/s is the derivative of the position vector.

[tex]If\: f(t)=cos(\frac{\pi t}{3})\\f'(t)=-\frac{\pi }{3}sin(\frac{\pi t}{3})\\v(t)=-\frac{\pi }{3}sin(\frac{\pi t}{3})[/tex]

(b)Velocity after 2 seconds

When t=2

[tex]v(2)=-\frac{\pi }{3}sin(\frac{\pi *2}{3})\\=-0.91 ft/s[/tex]

The particle moves 0.91 ft/s in the opposite direction.

Final answer:

The velocity v(t) of a particle moving with function s=f(t)=cos(πt/3) is given by v(t) = -(π/3)sin(πt/3). When t=2 seconds, the velocity of the particle is approximately -1.81 ft/s.

Explanation:

To find the velocity, v(t), at time t for the particle you need to find the derivative of s = f(t) = cos(πt/3) with respect to time, t. Using the chain rule, the derivative will be v(t) = -sin(πt/3) * (π/3), which simplifies to v(t) = -(π/3)sin(πt/3). This formula will provide the velocity of the particle at any time, t, within the given range.

To find the velocity of the particle after 2 seconds, substitute t = 2 into the velocity function. So, v(2) = -(π/3)sin(π*2/3). This simplifies to approximately -1.81 ft/s, when rounded to two decimal places. Therefore, the velocity of the particle at 2 seconds is -1.81 ft/s.

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To every linear transformation T from ℝ2 to ℝ2, there is an associated 2×2 matrix. Match the following linear transformations with their associated matrix. B 1. The projection onto the x-axis given by T(x,y)=(x,0) A 2. Counter-clockwise rotation by π/2 radians C 3. Clockwise rotation by π/2 radians A 4. Reflection about the y-axis B 5. Reflection about the x-axis F 6. Reflection about the line y=x A. (−1001) B. (1000) C. (100−1) D. (0−110) E. (01−10) F. (0110) G. None of the above

Answers

Answer:

1. B

2. D

3. E

4. A

5. C

6. F  

Step-by-step explanation:  

1. The projection onto the x-axis is given by T(x, y) = (x, o)  =(1 0 0 0) B  

2. Counter-clockwise rotation by π/2 radians C

= (0 - 1 1 0) D  

3. Clockwise rotation by π/2 radians

= (0 1 - 1 0) E  

4. Reflection about the y-axis

= (-1 0 0 1) A  

5. Reflection about the x-axis  = (1 0 0 - 1) C  

6. Reflection about the line y=x

(0 1 1 0) F  

For every line in a plane, there is a linear transformation that reflects the vector about that line. The easiest way to answer a question like this is to figure out where the standard basic vector is, e1 and e2. Write the answers at the column of the matrix. Letting As be the matrix corresponding to the linear transformation s. It is easier to see that e1 gets carried to e2 and e2 gets carried to - e1

As= (0 - 1 1 0)

Final answer:

The answer identifies and correlates different types of linear transformations in ℝ2 to ℝ2 space with their corresponding 2×2 matrices, considering operations such as projection onto axis, clockwise and counter-clockwise rotations, and reflections about axes or a line.

Explanation:

The question is about matching linear transformations with their associated 2×2 matrices.

The projection onto the x-axis given by T(x,y)=(x,0) would be represented by a matrix that eliminates the y-component, so its matrix is (1000). Counter-clockwise rotation by π/2 radians corresponds to the matrix (01−10), as it reverses the entries and changes the sign of the y-component. Clockwise rotation by π/2 radians corresponds to the matrix (0−110), as it also switches the entries, but with a positive sign for the y-component. Reflection about the y-axis inverts the sign of the x-component, corresponding to the matrix (−1001). Reflection about the x-axis influences the sign of the y-component, thus corresponding to the matrix (010-1). Lastly, reflection about the line y=x equates to exchange the roles of x and y and hence represented by the matrix (0110).

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the second and third terms in the following fibonacci sequence are X and Y. write down algebraic expressions for the first, fourth and fifth terms

Answers

Answer:

(Y-X), X, Y, (X+Y), (X+Y)+Y, ...

Step-by-step explanation:

FIBONACHI SEQUENCE IS A SPECIAL MATHEMATICAL SEQUENCE IN W/C YOU HAVE TO ADD THE LAST AND THE NEXT TERM TO GET THE FOLLOWING TERM, IF SO.. TO GET THE LAST TERM, JUST REDUCE THE 3RD TERM TO YOUR 2ND TERM

TO GET THE 4RTH AMD 5TH TERM, JUST ADD THE FLLOWING CONSECITIVE TERM AS SHOWN IN THE ANSWER

A newspaper published an article about a study in which researchers subjected laboratory gloves to stress. Among 279 vinyl gloves, 60% leaked viruses. Among 279 latex gloves, 14% leaked viruses. See the accompanying display of the technology results. Using a 0.10 significance level, test the claim that vinyl gloves have a greater virus leak rate than latex gloves. Let vinyl gloves be population 1. Identify: null, alternative hypothesis, test statistic, and P-value.

The P-value is (1) the significance level ?, so (2) the null hypothesis. There is (3) evidence to support the claim that vinyl gloves have a greater virus leak rate than latex gloves.

1) greater than / less than 2) reject / fail to reject 3) sufficient / insufficient

(Table at bottom of question)

Technology results:

Pooled proportion: 0.37

Test statistic, z: 11.3049

Critical z: 1.2816

P-value: 0.0000

80% Confidence interval: 0.4163430 < p1 ? p2 < 0.5083882

Answers

Answer:

a) H0: Null Hypothesis: P1 = P2

HA: Alternative Hypothesis:P1> P2

The P-value is less than the significance level.

Therefore, Reject the null hypothesis

In conclusion, there is enough evidence to support the claim that vinyl gloves have a greater virus leak rate than latex gloves.

Step-by-step explanation:

(a) From the information given, we can identify the null hypothesis and alternative hypothesis.

H0: Null Hypothesis: P1 = P2

HA: Alternative Hypothesis:P1> P2

(b) n1 which is size of sample 1 = 279

p1 which is proportion of sample 1= 0.60

n2 which is size ofsample 2 = 279

p2 which is proportion of sample 2 = 0.14

P=n1p1+n2p2 / n1+n2

=279 × 0.60+279 × 0.14/279+279

=0.37

Q = 1- P = 0.63

SE= √PQ(1/n1+1/n2)

= √ 0.37 × 0.63(1/279+1/279)=0.0409

So,

Test statistic is:

Z = (p1 - p2) /SE

= (0.60 - 0.14)/0.0409

= 11.3049

(c) The able of Area Under Standard Normal Curve gives the following area =

0.5 approximately.

So,

P-value = 0.5 - 0.5 nearly =0 nearly

(d)From the information derived, the P-value is less than the significance level.

Therefore, Reject the null hypothesis

In conclusion, there is enough evidence to support the claim that vinyl gloves have a greater virus leak rate than latex gloves.

206, 254, 240, 203, 191, 208, 218, 235, 242, 237, 213, 222, 228, 201, 225, 186 whats the 25th percentile

Answers

Answer:

Q1 or the 25th percentile is 204.5

Step-by-step explanation:

Combine all data values in TI-84, excel, or other software and make a box and whisker plot. The Q1 is the first vertical line on the plot

A food safety inspector is called upon to investigate a restaurant with a few customer reports of poor sanitation practices. The food safety inspector uses a hypothesis testing framework to evaluate whether regulations are not being met. If he decides the restaurant is in gross violation, its license to serve food will be revoked.

What is a Type 1 Error in this context?

Answers

Answer:

P (Type I Error) = P (Revokes the license | Restaurant is not in gross violation)

Step-by-step explanation:

A type I error occurs when we reject a true null hypothesis (H₀). It is the probability of rejecting the null hypothesis when the null hypothesis is true.

The type I error is also known as the level of significance. It is denoted by α .

P (Type I Error) = P (Rejecting H₀ | H₀ is true) = α.

In this case, the food inspector uses a hypothesis testing framework to evaluate whether regulations are not being met.

He decides the the restaurant's license to serve food will be revoked if the restaurant is in gross violation.

So the hypothesis is defined as:

H₀: The restaurant is not in gross violation.

Hₐ: The restaurant is in gross violation.

The type I error will be committed by the food inspector if he concludes that the the restaurant is in gross violation and revokes their license, when in fact the restaurant is not in gross violation.

α = P (Revokes the license | Restaurant is not in gross violation)

Final answer:

A Type 1 Error in this context would be when the food safety inspector incorrectly identifies the restaurant as violating sanitation regulations when in reality, it was following all necessary practices. It’s the wrongful rejection of the null hypothesis.

Explanation:

In statistical hypothesis testing, a Type 1 Error occurs when a true null hypothesis is rejected. In the context of the food safety inspector's investigation, the null hypothesis would likely be that the restaurant is abiding by all required sanitation practices. Therefore, a Type 1 Error would be if the food safety inspector concludes that the restaurant is in serious violation of sanitation regulations and revokes its license, but in actuality, the restaurant was not violating any regulations, i.e., the inspector incorrectly identified the restaurant as unclean and unhealthy.

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The plane x+y+2z=8 intersects the paraboloid z=x2+y2 in an ellipse. Find the points on this ellipse that are nearest to and farthest from the origin. Point farthest away occurs at ( , , ). Point nearest occurs at (

Answers

Answer:

The minimum distance of   √((195-19√33)/8)  occurs at  ((-1+√33)/4; (-1+√33)/4; (17-√33)/4)  and the maximum distance of  √((195+19√33)/8)  occurs at (-(1+√33)/4; - (1+√33)/4; (17+√33)/4)

Step-by-step explanation:

Here, the two constraints are

g (x, y, z) = x + y + 2z − 8  

and  

h (x, y, z) = x ² + y² − z.

Any critical  point that we find during the Lagrange multiplier process will satisfy both of these constraints, so we  actually don’t need to find an explicit equation for the ellipse that is their intersection.

Suppose that (x, y, z) is any point that satisfies both of the constraints (and hence is on the ellipse.)

Then the distance from (x, y, z) to the origin is given by

√((x − 0)² + (y − 0)² + (z − 0)² ).

This expression (and its partial derivatives) would be cumbersome to work with, so we will find the the extrema  of the square of the distance. Thus, our objective function is

f(x, y, z) = x ² + y ² + z ²

and

∇f = (2x, 2y, 2z )

λ∇g = (λ, λ, 2λ)

µ∇h = (2µx, 2µy, −µ)

Thus the system we need to solve for (x, y, z) is

                           2x = λ + 2µx                         (1)

                           2y = λ + 2µy                       (2)

                           2z = 2λ − µ                          (3)

                           x + y + 2z = 8                      (4)

                           x ² + y ² − z = 0                     (5)

Subtracting (2) from (1) and factoring gives

                     2 (x − y) = 2µ (x − y)

so µ = 1  whenever x ≠ y. Substituting µ = 1 into (1) gives us λ = 0 and substituting µ = 1 and λ = 0  into (3) gives us  2z = −1  and thus z = − 1 /2 . Subtituting z = − 1 /2  into (4) and (5) gives us

                            x + y − 9 = 0

                         x ² + y ² +  1 /2  = 0

however, x ² + y ² +  1 /2  = 0  has no solution. Thus we must have x = y.

Since we now know x = y, (4) and (5) become

2x + 2z = 8

2x  ² − z = 0

so

z = 4 − x

z = 2x²

Combining these together gives us  2x²  = 4 − x , so

2x²  + x − 4 = 0 which has solutions

x =  (-1+√33)/4

and

x = -(1+√33)/4.

Further substitution yeilds the critical points  

((-1+√33)/4; (-1+√33)/4; (17-√33)/4)   and

(-(1+√33)/4; - (1+√33)/4; (17+√33)/4).

Substituting these into our  objective function gives us

f((-1+√33)/4; (-1+√33)/4; (17-√33)/4) = (195-19√33)/8

f(-(1+√33)/4; - (1+√33)/4; (17+√33)/4) = (195+19√33)/8

Thus minimum distance of   √((195-19√33)/8)  occurs at  ((-1+√33)/4; (-1+√33)/4; (17-√33)/4)  and the maximum distance of  √((195+19√33)/8)  occurs at (-(1+√33)/4; - (1+√33)/4; (17+√33)/4)

In this question, we have 2 constraints:

The plane                        g ( x , y , z ) = x + y + 2 z - 8

The paraboloid             h ( x , y , z ) = x² + y² - z

We need to apply Lagrange Multipliers to answer it

The solution are:

The nearest point P = ( -9.06/4   ,   -9.06 /4  ,  6.23 )

The farthest point Q  (  (7.06) /4  ,  (7.06) /4 ,  10.26)

The Objective Function (F) is the distance between the ellipse and the origin, In this case,  we don´t need to know the equation of the ellipse

The Objective Function is

F = √ x² + y² + z²    and as this function has the same critical points that

F  = x² + y² + z²  we will use this one

Then:

     δF/δx  = 2×x               δF/δy  = 2×y                 δF/δz = 2×z

   λ ×δg/δx =  λ                  λ δg/δy = λ                  λ δg/δz = 2× λ    

   μ× δh/δx = 2× μ×x         μ× δh/δy = 2× μ×y        μ× δh/δz= - μ

Therefore we get our five equations.

2×x  =  λ   +  2× μ×x      (1)

2×y  =  λ   +  2× μ×y      (2)

2×z  = 2× λ  -  μ             (3)

x + y + 2 z - 8 = 0          (4)

x² + y² - z = 0                (5)

Subtracting equation (2) from equation (1)

2×x  - 2×y  = 2× μ×x -  2× μ×y

( x - y ) =  μ × ( x - y )       then   μ = 1   and by substitution in eq. (2)

2×y  =  λ   +  2×y        then       λ  = 0

From eq. (3)

2×z  = - 1                                   z = -1/2

By subtitution in eq. (4) and (5)

x  +  y  - 1 - 8 = 0     ⇒   x  +  y  = 9

x² + y² + 1/2  = 0        this equation has no solution.

If we make  x = y

Equation (4) and (5) become

2× x + 2× z = 8

2×x² - z = 0        ⇒         z = 2×x²

2× x + 4×x² = 8     ⇒   2×x² + x - 8 = 0

Solving for x          x₁,₂ = ( -1 ± √ 1 + 64 ) / 4

x₁,₂ = ( -1 ± √65 ) 4

x₁ = (-1 + √65) /4            x₂ = ( -1 - √65) /4          √ 65  = 8.06

x₁ = 1.765            x₂ = - 2.265

And  z = 2×x²      ⇒      z₁ =  6.23          z₂  =

And critical points are:

P ( x₁  y₁  z₁ )      (  (7.06) /4  ,  (7.06) /4 ,  6.23 )

Q ( x₂  y₂ z₂ )      ( -9.06/4   ,   -9.06 /4  ,  10.26 )

And by simple  inspeccion we see That

minimum distance is the point P = ( -9.06/4   ,   -9.06 /4  ,  6.23 )

the point Q  (  (7.06) /4  ,  (7.06) /4 ,  10.26) is the farthest point

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An open box with a square base is to be made from a square piece of cardboard 24 inches on a side by cutting out a square from each corner and turning up the sides. If the volume V of the box is a function of the length x of the side of the square cut from each corner, for what value of x is V the largest

Answers

The value of x that maximizes the volume V is x = 2 inches.

This means that by cutting 2-inch squares from each corner of the 24-inch square cardboard, you'll create an open box with the largest possible volume.

We have,

To solve this problem, we need to express the volume of the open box in terms of the length x of the side of the square cut from each corner, and then find the value of x that maximizes this volume.

Let's denote:

Side length of the original square cardboard = 24 inches

Side length of the cut square from each corner = x inches

The dimensions of the resulting box would be:

Length = (24 - 2x) inches (since we're removing x from both sides)

Width = (24 - 2x) inches (same as length)

Height = x inches

The volume V of the box can be calculated by multiplying these dimensions:

V = Length * Width * Height

V = (24 - 2x) * (24 - 2x) * x

Now, we'll simplify this expression for V:

V = x * (24 - 2x)²

To find the value of x that maximizes V, we need to find the critical points of the function and then analyze the behaviour around those points.

Take the derivative of V with respect to x:

dV/dx = 24x - 12x²

Set the derivative equal to zero and solve for x to find the critical points:

24x - 12x² = 0

12x(2 - x) = 0

This gives us two critical points: x = 0 and x = 2.

Now we need to determine which critical point corresponds to a maximum value of V.

To do this, we can analyze the second derivative of V with respect to x:

d²V/dx² = 24 - 24x

Evaluate the second derivative at each critical point:

For x = 0: d²V/dx² = 24 (positive value)

For x = 2: d²V/dx² = 24 - 24(2) = -24 (negative value)

Since the second derivative is negative at x = 2, it indicates that this critical point corresponds to a maximum.

Therefore,

The value of x that maximizes the volume V is x = 2 inches.

This means that by cutting 2-inch squares from each corner of the 24-inch square cardboard, you'll create an open box with the largest possible volume.

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Final answer:

To find the value of x that maximizes the volume of the box, we need to express the volume as a function of x. Then, we can take the derivative of the volume function with respect to x, set it equal to zero, and solve for x. Finally, we substitute the value of x back into the volume function to find the maximum volume.

Explanation:

To find the value of x that maximizes the volume of the box, we need to express the volume as a function of x. Let's start by finding the dimensions of the box after cutting out the squares from each corner. Since the original square has sides of 24 inches, each side of the base of the box will be 24 - 2x inches. The height of the box will be x inches.

The volume of a box is given by the formula V = length x width x height. In this case, the length and width of the base of the box are the same, so we can simplify the formula to V = (24 - 2x)^2 * x.

To find the value of x that maximizes the volume, we can take the derivative of the volume function with respect to x, set it equal to zero, and solve for x. Once we find the value of x, we can substitute it back into the volume function to find the maximum volume.

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A 1980 study was conducted whose purpose was to compare the indoor air quality in offices where smoking was permitted with that in offices where smoking was not permitted. Measurements were made of carbon monoxide (CO) at 1:20 p.m. in 40 work areas where smoking was permitted and in 40 work areas where smoking was not permitted. Where smoking was permitted, the mean CO level was 11.6 parts per million (ppm) and the standard deviation CO was 7.3 ppm. Where smoking was not permitted, the mean CO was 6.9 ppm and the standard deviation CO was 2.7 ppm.

To test for whether or not the mean CO is significantly different in the two types of working environments, perform a t-test for unequal variance and report the p-value

Answers

Answer:

The null hypothesis is not rejected.

There is no enough evidence to support the claim that the CO level is lower  in non-smoking working areas compared to smoking work areas.

P-value = 0.07.

Step-by-step explanation:

We have to perform a test on the difference of means.

The claim that we want to test is that CO is less present in no-smoking work areas.

Then, the null and alternative hypothesis are:

[tex]H_0: \mu_1-\mu_2=0\\\\H_a:\mu_1-\mu_2 > 0[/tex]

being μ1: mean CO level in smoking work areas, and μ2: mean CO level in no-smoking work areas.

The significance level is assumed to be 0.05.

Smoking areas sample

Sample size n1=40.

Sample mean M1=11.6

Sample standard deviation s1=7.3

No-smoking areas sample

Sample size n2=40

Sample mean M2=6.9

Sample standard deviation s2=2.7

First, we calculate the difference between means:

[tex]M_d=M_1-M_2=11.6-7.3=4.3[/tex]

Second, we calculate the standard error for the difference between means:

[tex]s_{M_d}=\sqrt{\dfrac{\sigma_1^2}{n_1}+\dfrac{\sigma_2^2}{n_2}}=\sqrt{\dfrac{7.3^2}{40}+\dfrac{2.7^2}{40}}=\sqrt{\dfrac{53.29+7.29}{40}}=\sqrt{\dfrac{60.58}{40}}\\\\\\s_{M_d}=\sqrt{1.5145}=1.23[/tex]

Now, we can calculate the t-statistic:

[tex]t=\dfrac{M_d-(\mu_1-\mu_2)}{s_{M_d}}=\dfrac{4.3-0}{1.23}=3.5[/tex]

The degrees of freedom are calculated with the Welch–Satterthwaite equation:

[tex]df=\dfrac{(\dfrac{s_1^2}{n_1}+\dfrac{s_2^2}{n_2})^2}{\dfrac{s_1^4}{n_1(n_1-1)}+\dfrac{s_2^4}{n_2(n_2-1)}} \\\\\\\\df=\dfrac{(\dfrac{7.3^2}{40}+\dfrac{2.7^2}{40})^2}{\dfrac{7.3^4}{40(39)}+\dfrac{2.7^4}{40(39)}} =\dfrac{(\dfrac{53.29}{40}+\dfrac{7.29}{40})^2}{\dfrac{2839.82}{1560}+\dfrac{53.14}{1560}} \\\\\\\\df=\dfrac{1.5145^2}{1.8545}=\dfrac{2.2937}{1.8545}=1.237[/tex]

The P-value for this right tail test, with 1.237 degrees of freedom and t=3.5 is:

[tex]P-value=P(t>3.5)=0.07[/tex]

The P-value is bigger than the significance level, so the effect is not significant. The null hypothesis is not rejected.

There is no enough evidence to support the claim that the CO level is lower  in non-smoking working areas compared to smoking work areas.

Final answer:

The p-value, which indicates the likelihood that the difference in CO levels in the work areas is due to chance, can be computed from the mean CO levels and the standard deviations using a t-test for unequal variance. The computation requires several steps, including calculating the degrees of freedom and the t-statistic.

Explanation:

To conduct the t-test for unequal variance, we need to follow several steps. Below are the necessary steps:

Compute the degrees of freedom: df = (s1^2/n1 + s2^2/n2)^2 / { [ (s1^2/n1)^2 / (n1-1) ]  + [ (s2^2/n2)^2 / (n2-1) ] } where s1 and s2 are the standard deviations, n1 and n2 are the sample sizes. Compute the t-statistic: t = (x1 - x2) / sqrt (s1^2/n1 + s2^2/n2) where x1 and x2 are the sample means. Finally, use a t-distribution table or an online calculator to find the p-value based on the t-statistic and the degrees of freedom

 

In this scenario, the mean CO levels and standard deviations in work areas where smoking was permitted and not permitted are given. By plugging these into the formulas, we can find the t-value and then use the t-distribution to find the corresponding p-value.

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(4x^2-10x+6) divide (4x+2)

Answers

Answer:

x = 1 or x = 3/2

Step-by-step explanation:

Solve for x:

(4 x^2 - 10 x + 6)/(4 x + 2) = 0

Multiply both sides by 4 x + 2:

4 x^2 - 10 x + 6 = 0

The left hand side factors into a product with three terms:

2 (x - 1) (2 x - 3) = 0

Divide both sides by 2:

(x - 1) (2 x - 3) = 0

Split into two equations:

x - 1 = 0 or 2 x - 3 = 0

Add 1 to both sides:

x = 1 or 2 x - 3 = 0

Add 3 to both sides:

x = 1 or 2 x = 3

Divide both sides by 2:

Answer: x = 1 or x = 3/2

What is the equation of the line that has a slope of -3 and goes through the point (3,-1)

Answers

Answer:

y = -3x+8

Step-by-step explanation:

We can use the slope intercept form of an equation

y = mx+b  where m is the slope and b is the y intercept

y = -3x+b

Substitute the point into the equation

-1 = -3(3)+b

-1 = -9+b

Add 9 to each side

-1+9 = -9+9+b

8 =b

y = -3x+8

A test of [tex]H_{0}[/tex]: μ = 20 versus [tex]H_{1}[/tex]: μ > 20 is performed using a significance level of ∝ = 0.05. The value of the test statistic is z = 1.47.


If the true value of μ is 25, does the test conclusion result in a Type I error, a Type II error, or a Correct decision?

Answers

Answer:

Type II error

Step-by-step explanation:

Type 1 error occurs when:

We reject a True Null Hypothesis

Type 2 error occurs when:

We fail to reject a wrong Null Hypothesis.

The given hypothesis are:

[tex]H_{o}: \mu=20\\\\ H_{a}:\mu>20[/tex]

Level of significance = α = 0.05

The calculated z test statistic = z = 1.47

In order to make a decision we first need to convert z = 1.47 to its equivalent p-value. From the z-table the p value for z score being greater than 1.47 comes out to be:

p-value = 0.0708

Since, p-value is greater than the level of significance, we fail to reject the Null Hypothesis.

It is given that the true value of μ is 25. If the true value of μ is 25, then the Null hypothesis was false. But from the test we performed, we failed to reject the Null Hypothesis.

Since, we failed to reject a False Null Hypothesis, the conclusion resulted in a Type II error.

What is the arc measure of the minor arc BC in degrees?
285
(20y - 11)
(4y+6)
(7y - 7)

Answers

Answer:

Step-by-step explanation:

131

The radius of a cylinder is 3 cm and the height is 6 cm.

Find the Surface Area. (hint: Use the answer from the previous question.)

Answers

Answer

Step-by-step explanation:

A=2πrh+2πr2=2·π·3·6+2·π·32≈169.646

Answer: 169.65
Use the formula A= 2pi * r * h + 2pi * r sq.



please answer all of them there are 3 pages cuz i couldnt fit them all only 10 questions tho please answer it like this
1:
2:
3:
4:

Answers

Answer:

1:C

2:B

3:A

4:B

5:D

6:D

7:A

8:C

9:C

10:B

Step-by-step explanation:

(5) In the center of the monument are two concentric circles of igneous rock pillars, called bluestones. The construction of these circles was never completed. These circles are known as the Bluestone Circle and the Bluestone Horseshoe. The stones in these two formations were transported to the site from the Prescelly Mountains in Pembrokeshire, southwest Wales. Excavation at the center of the monument revealed an antler, an antler tine, and an animal bone. Each artifact was submitted for dating. It was determined that this sample of three artifacts had a mean age of 2193.3 BCE, with a standard deviation of 104.1 years. Assume that the ages are normally distributed with no obvious outliers. Use an α = 0.05 significance level to test the claim that the population mean age of the Bluestone formations is different from Corbin's declared mean age of the ditch, that is, 2950 BCE.

Answers

Answer:

There is enough evidence, at a significance level of 0.05, that the population mean age of the Bluestone formations is different from 2950 BCE.

Step-by-step explanation:

We have a sample and we want to perform a hypothesis test on the mean.

The null hypothesis is the Corbin's declared age (2950 BCE). The alternative hypothesis states that the age differ from that value.

They can be expressed as:

[tex]\H_0:\mu=2950\\\\H_a:\mu\neq2950[/tex]

The significance level is 0.05.

The sample has a size of n=3, a mean of 2193.3 BCE and a standard deviation of 104.1 years.

As the standard deviation is estimated from the sample, we have to calculate the t-statistic.

[tex]t=\dfrac{\bar x-\mu}{s/\sqrt{n}}=\dfrac{2193.3-2950}{104.1/\sqrt{3}}=\dfrac{-756.7}{60.1}=-12.59[/tex]

The degrees of freedom for this test are:

[tex]df=n-1=3-1=2[/tex]

The critical value for a two side test with level of significance α=0.05 and 2 degrees of freedom is t=±4.271.

As the statistic t=-12.59 lies outside of the acceptance region, the null hypothesis is rejected.

There is enough evidence, at a significance level of 0.05, that the population mean age of the Bluestone formations is different from 2950 BCE.

What type of symmetry can the graph of a quadratic function have?

A. Symmetry about the x-axis

B. Symmetry about the y-axis

C. Symmetry about the line y=x

D. No symmetry

Answers

Answer:

B

Step-by-step explanation:

Option B is correct. A quadratic function can have symmetry about the y-axis.

What is quadratic equation?

A quadratic equation is a second-order polynomial equation in a single variable x , ax²+bx+c=0. with a ≠ 0 .

A quadratic function can have symmetry about the axis of symmetry, which is a vertical line that passes through the vertex of the parabola. The axis of symmetry is given by the equation x = -b/(2a)

where a and b are the coefficients of the quadratic function ax² + bx + c.

If a quadratic function has symmetry about the x-axis, then its equation is of the form y = ax² + c, where a and c are constants.

If it has symmetry about the y-axis, then its equation is of the form y = ax², where a is a constant.

Therefore, Option B is correct. A quadratic function can have symmetry about the y-axis.

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consider circle O, in which arc XY measures 16 pie cm. The length of a radius of the circle is 32 cm. What is the circumference of the circle?

Answers

Answer:64 pi units

What is the ratio of the arc length to the circumference?Answer: 1/4

What is the measure of central angle XOY?Answer: 90 degrees

Answer:

1. 64 pi units

2. 1/4

3. 90°

Step-by-step explanation: edge

An architect is making a model of a proposed office building with the dimensions shown. To fit on a display, the longest side of the architect's
model must be 30 inches long. To make the model geometrically similar to the proposed building, what should the width and the height of the
model be?

A. Width = 20 inches, height = 8 inches

B. Width = 20 inches, height = 12 inches

C. Width = 25 inches, height = 16 inches

D. Width = 25 inches, height = 20 inches

E. Width = 20 inches, height = 25 inches

Answers

Answer:

25 20

Step-by-step explanation:

D. Width = 25 inches, height = 20 inches

Follow the steps to finish solving the equation –3x + 18 = 7x.
1. Add 3x to both sides to isolate the variable term.
2. Divide both sides by 10.

Answers

18/10

Step-by-step explanation:

Answer:

18/10

Step-by-step explanation:

Just did the question

Mandy wants to buy a variety of beverages for her birthday party. She wants to make sure she has enough to drink for all her friends, so she decides to buy 10 liters of beverages. If she buys at least one container of each beverage, what combination of beverages can she buy to equal exactly 10 liters? Beverages at the store:
2,000 millilitres of soda, 2.5 liters of apple juice, 1,500 millilitres of fruit punch, 2 liters of lemonade

Answers

Answer:

Soda x 2

Apple Juice x 1

Fruit Punch x 1

Lemonade x 1

and

Soda x 1

Apple Juice x 1

Fruit Punch x 1

Lemonade x 2

Step-by-step explanation:

Amounts:

Soda 2L

Apple Juice 2.5L

Fruit Punch 1.5L

Lemonade 2L

S + A + FP + L = 8L

So we need 2 L more. The only way of doing this is by either having 2 lots of soda or 2 lots of lemonade.

The combination of beverages she can purchased;

Soda = 2 container

Apple juice = 1 container

Fruit punch= 1 container

Lemonade = 1 container

Logical reasoning:

The quantity of Beverages present  at the store ;

Soda = 2000ml = 2L

Apple Juice = 2.5L

Fruit Punch = 1.5L

Lemonade =  2L

We have to buy  exactly 10 liters but it should be at least one container of each beverage.

Soda + Apple juice + Fruit Punch + Lemonade = 8L

So we need 2 L more.

The only way of doing this is by either having 2 container of soda or 2 container of lemonade.

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What is the range of the data below?


50
60
70
80
90
100
оооо

Answers

Answer:

50 all you have to do is subtract the least and the biggest number

Step-by-step explanation:

50 subtract the biggest number from the bo

An experiment was performed to compare the wear of two different laminated materials. Twelve pieces of material 1 were tested by exposing each piece to a machine measuring wear. Ten pieces of material 2 were similarly tested. In each case, the depth of wear was observed. The samples of material 1 gave an average (coded) wear of 85 units with a sample standard deviation of 4, while the samples of material 2 gave an average of 81 with a sample standard deviation of 5. Can we conclude at the 0.05 level of significance that the abrasive wear of material 1 exceeds that of material 2 by more than two units? Assume the populations to be approximately normal with equal variances pdf

Answers

Answer:

At 0.05 level of significance, the abrasive wear of material 1 exceeds that of material 2 by more than 2 units

Step-by-step explanation:

We hypothesize that mean difference between abrasive wear of material 1 and material 2 is greater than 2.

So we write the null hypothesis [tex]H_0 : \mu_1 - \mu_2 >2[/tex],

and the alternative hypothesis [tex]H_1: \mu_1 - \mu_2 \leq 2[/tex].

We will find the T-score as well as the p-value. If the p-value is less than the level of significance, we will reject the null hypothesis, i.e. we will conclude that the abrasive wear of material 1 is less than that of material 2. Otherwise, we will accept the null hypothesis.

Since the variance is unknown and assumed to be equal, we will use the pooled variance

[tex]s_p^2 = \frac{(n_1-1)s_1^2 + (n_2-1)s_2^2}{n_1+n_2-2} = 20.05[/tex],

where [tex]n_1 = 12, n_2 =10, s_1 =4, s_2 = 5[/tex].

The mean of material 1 and material 2 are [tex]\mu_1 =85, \mu_2=81[/tex] respectively and mean difference [tex]d[/tex] is equal to 4. The hypothesize difference [tex]d_0[/tex] is equal to 2.

To find the T-score, we use the following formula

[tex]T = \frac{d - d_0}{\sqrt{\frac{s_p^2}{n_1} + \frac{s_p^2}{n_2} }}[/tex]

Substituting all the values into the T-score formula gives us [tex]T = 1.04[/tex], and the respective p-value is equal to 0.31. This means we have enough statistical evidence not to reject the null hypothesis, and at 5% significance level, the abrasive wear of material 1 exceeds that of material 2 by more than 2 units.

Evaluate and simplify the expression when x=1 and y=2. 3(×+2y)-2x+10=?​

Answers

23
I guess that is the answer

Answer:

Step-by-step explanation:

Just for some extra closure lol the answer is indeed 23. :)

Suppose that two balanced dice, a red die, and a green die, are rolled. Let Y denote the value of G - R where G represents the number on the green die and R represents the number on the red die. What are the possible values of the random variable Y?

Answers

Answer:

-5,-4,-3,-2,-1,0,1,2,3,4,5

Step-by-step explanation:

The sample space for the two balanced dice, a red die, and a green die is given below in the pair (G,R)

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)

(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)

(3,1) (3,2) (3,3) (3,4) (3,5) (3,6)

(4,1) (4,2) (4,3) (4,4) (4,5) (4,6)

(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)

(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)

For each pair, Y=G-R is presented below:

0 -1 -2 -3 -4 -5

1 (2,2) (2,3) (2,4) (2,5) (2,6)

2 (3,2) (3,3) (3,4) (3,5) (3,6)

3 (4,2) (4,3) (4,4) (4,5) (4,6)

4 (5,2) (5,3) (5,4) (5,5) (5,6)

5 (6,2) (6,3) (6,4) (6,5) (6,6)

The first column and row is representative of the values which will be obtained throughout the table.

Therefore, the possible values of the random variable Y are:

-5,-4,-3,-2,-1,0,1,2,3,4,5

The possible values of Y are its sample space, and the values are 0, -1, -2, -3, -4, -5, 5, 4, 3, 2 and 1

The sample space of the green die is:

[tex]G= \{1,2,3,4,5,6\}[/tex]

The sample space of the red die is:

[tex]R= \{1,2,3,4,5,6\}[/tex]

When the numbers on both dice are combined, we have the following possible outcomes

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6) , (2,1) (2,2) (2,3) (2,4) (2,5) (2,6) , (3,1) (3,2) (3,3) (3,4) (3,5) (3,6) , (4,1) (4,2) (4,3) (4,4) (4,5) (4,6) , (5,1) (5,2) (5,3) (5,4) (5,5) (5,6) , (6,1) (6,2) (6,3) (6,4) (6,5) (6,6)

Subtract the second outcomes from the first, to get Y

(0) (-1) (-2) (-3) (-4) (-5) , (-1) (0) (-1) (-2) (-3) (-4) , (2) (1) (0) (-1) (-2) (-3) , (3) (2) (1) (0) (-1) (-2) , (4) (3) (2) (1) (0) (-1) , (5) (4) (3) (2) (1) (0)

List out the unique numbers:

(0) (-1) (-2) (-3) (-4) (-5) (5) (4) (3) (2) (1)

Hence, the possible values of Y are 0, -1, -2, -3, -4, -5, 5, 4, 3, 2 and 1

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5 inches +?inches = 1 foot?

Answers

Answer:

7 inches hope this helps

Step-by-step explanation:

Answer:

7 inches

Step-by-step explanation:

12 inches is a foot

Can somone help me with 1,2,3 ????

Answers

Answer:

This is a weird assignment

Step-by-step explanation:

1)    7.5 minute per mile

10 convert hours to min (900 min) and then simply the unit of 6771 miles by 900 min. The objective is to know how far you travel in one minute.

3) Chose any country in South America:

Brazil, Argentina, Peru, Columbia, Venezuela, Bolivia, etc.

A certain front-loading washing machine has a drum of diameter 23.3 inches. A small tennis ball placed inside spins in a vertical circle pressed against the inner wall of the drum. How quickly would the drum have to spin (in radians per second) in order to ensure that the tennis ball remained pinned against the wall for the entire cycle without falling off?

Answers

Answer:

33.12 rad/s

Step-by-step explanation:

We are given that

Diameter=d=23.3 in

Radius,=[tex]r=\frac{d}{2}=\frac{23.3}{2}=11.65 in=11.65\times 0.0254= 0.29591 m[/tex]

1 in=0.0254 m

We have to find the angular speed of drum would have to spin.

Force=[tex]mg[/tex]

Centripetal force=[tex]m\omega^2 r[/tex]

[tex]mg=m\omega^2 r[/tex]

[tex]\omega^2=\frac{g}{r}[/tex]

[tex]\omega=\sqrt{\frac{g}{r}}[/tex]

Where [tex]g=9.8m/s^2[/tex]

[tex]\omega=\sqrt{\frac{9.8}{0.29591}[/tex]

[tex]\omega=33.12 rad/s[/tex]

What is the measure of angle DEG on circle O? Please help! Picture included!

Answers

I don't know how to do that. Only one angle is given and no relationships between the triangles or any lines are given.

Answer:

The answer is 50.

Step-by-step explanation:

Write an expression that gives the requested sum.
The sum of the first 20 terms of the geometric sequence with first term 6 and common ratio 3
s20 =

Answers

Answer:The expression to give the requested sum after simplifying, [tex]S_{20}[/tex] = [tex]{3(3^{20}-1) }[/tex]

Step-by-step explanation:

To find the sum of first 20 terms,

a = 6, r = 3

By formula, [tex]S_{n} = \frac{a(r^{n}-1) }{r-1}[/tex]

substitute the values in the above formula, the equation becomes,

[tex]S_{20} = \frac{6(3^{20}-1) }{3-1}[/tex]

[tex]S_{20} = \frac{6(3^{20}-1) }{2}[/tex]

[tex]S_{20}[/tex] = [tex]{3(3^{20}-1) }[/tex]

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