A research study investigated the adhesion of various biofilms to solid surfaces for possible use in environmental technologies. Suppose that for the bacterial strain Acinetobacter, five measurements gave readings of 2.69, 5.76, 2.67, 1.62, and 4.12 dyne-cm2. Assume that the standard deviation is known to be 0.66 dyne-cm2 Find a 95% two-sided confidence interval for the mean adhesion.

Answers

Answer 1

Answer:

[tex]3.372-1.96\frac{0.66}{\sqrt{5}}=2.793[/tex]    

[tex]3.372+1.96\frac{0.66}{\sqrt{5}}=3.951[/tex]    

We are 95% confident that the true mean for the adhesion to solid surfaces in dyne-cm2  is between (2.793; 3.951)

Step-by-step explanation:

Data provided

2.69, 5.76, 2.67, 1.62, and 4.12

We can calculate the sample mean with this formula:

[tex]\bar X =\frac{\sum_{i=1}^n X_i}{n}[/tex]

And replacing we got:

[tex]\bar X=3.372[/tex] represent the sample mean

[tex]\mu[/tex] population mean (variable of interest)

[tex]\sigma=0.66[/tex] represent the population standard deviation

n=5 represent the sample size  

Confidence interval :

The two sided confidence interval for the true mean is given by:

[tex]\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}[/tex]   (1)

We have the confidence level given of 0.95 or 95%, the value of [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.025,0,1)".And we see that [tex]z_{\alpha/2}=1.96[/tex]

Replacing into the formula for the interval we have this:

[tex]3.372-1.96\frac{0.66}{\sqrt{5}}=2.793[/tex]    

[tex]3.372+1.96\frac{0.66}{\sqrt{5}}=3.951[/tex]    

We are 95% confident that the true mean for the adhesion to solid surfaces in dyne-cm2  is between (2.793; 3.951)

Answer 2

Final answer:

The 95% confidence interval for the mean adhesion of the bacterial strain Acinetobacter, based on the given measurements and standard deviation, is [2.795, 3.949] dyne-cm².

Explanation:

The question asks us to find a 95% confidence interval for the mean adhesion of the bacterial strain Acinetobacter based on five given measurements and a known standard deviation. To calculate the confidence interval, we can use the formula for the confidence interval of the mean when the standard deviation is known:

mean ± Z*(standard deviation/√n),

where Z is the Z-value corresponding to the desired level of confidence from the standard normal distribution, and n is the sample size.

First, we need to calculate the mean of the given measurements:

Mean = (2.69 + 5.76 + 2.67 + 1.62 + 4.12) / 5 = 16.86 / 5 = 3.372 dyne-cm²

Since we are looking for a 95% confidence interval and the standard deviation (σ) is 0.66 dyne-cm² with a sample size (n) of 5, our formula becomes:

3.372 ± (Z * 0.66 / √5)

To find the appropriate Z-value, we look at the standard normal distribution table for a two-sided 95% confidence interval, which gives us a Z-value of approximately 1.96.

Plugging this Z-value into the formula, we can calculate the confidence interval:

3.372 ± (1.96 * 0.66 / √5) = 3.372 ± 0.577

Therefore, the 95% confidence interval for the mean adhesion is [2.795, 3.949] dyne-cm².


Related Questions

A certain flight arrives on time 8484 percent of the time. Suppose 143143 flights are randomly selected. Use the normal approximation to the binomial to approximate the probability that ​(a) exactly 108108 flights are on time. ​(b) at least 108108 flights are on time. ​(c) fewer than 124124 flights are on time. ​(d) between 124124 and 128128​, inclusive are on time. ​(a) ​P(108108​)equals=0.00200.0020 ​(Round to four decimal places as​ needed.) ​(b) ​P(Xgreater than or equals≥108108​)equals=0.99800.9980 ​(Round to four decimal places as​ needed.) ​(c) ​P(Xless than<124124​)equals=0.77960.7796 ​(Round to four decimal places as​ needed.) ​(d) ​P(124124less than or equals≤Xless than or equals≤128128​)equals=0.19230.1923 ​(Round to four decimal places as​ needed.)

Answers

Answer:

a) P(x=108)=0.0020

b) P(x≥108)=0.9980

c) P(x<124)=0.7794

d) P(124≤x≤128)=0.1925

Step-by-step explanation:

We know the population proportion, that is p=0.84.

We take a sample of size n=143.

We will use the normal approximation to the binomial distribution to model this problem.

The mean and standard deviation of the normal approximation to the binomial distribution will be:

[tex]\mu=np=143*0.84=120.12\\\\\sigma=\sqrt{np(1-p)}=\sqrt{143*0.84*0.16}=\sqrt{19.22}=4.38[/tex]

a) We have to calculate the probability that exactly 108 flights are on time.

As the normal distribution considers the random variable to be continous, we have to apply the continuity correction factor.

In this case, the probability of 108 flights on time can be calculated as P(107.5<x<108.5):

[tex]P(x=108)=P(107.5<x<108.5)=P(x<108.5)-P(x<107.5)\\\\\\ z_1=(x_1-\mu)/\sigma=(107.5-120.12)/4.38=-12.62/4.38=-2.88\\\\z_2=(x_2-\mu)/\sigma=(108.5-120.12)/4.38=-11.62/4.38=-2.65\\\\\\P(x<108.5)-P(x<107.5)=P(z<-2.65)-P(z<-2.88)\\\\P(x<108.5)-P(x<107.5)=0.0040-0.0020=0.0020[/tex]

b) Now we have to calculate that at least 108 flights are on time.

As the probability includes 108, the continuity factor will indicates that we calculate P(x>107.5). The z-value for x=107.5 has been already calculated in point a:

[tex]P(x\geq108)=P(x>107.5)=P(z>-2.88)=0.9980[/tex]

c) We have to calculate the probability that fewer than 124 flights are on time. According to the continuity factor, we have to calculate the probability P(x<123.5), as the flight number 124 is not included in the interval.

[tex]P(x<124)=P(x<123.5)=P(z<0.77)=0.7794\\\\\\z=(x-\mu)/\sigma=(123.5-120.12)/4.38=0.77[/tex]

d) We have to calculate the probability that between 124 and 128 flights, inclusive, are on time.

This interval corresponds to the probability P(123.5<x<128.5)

[tex]P(123.5<x<128.5)=P(x<128.5)-P(x<123.5)\\\\\\ z_1=(x_1-\mu)/\sigma=(128.5-120.12)/4.38=8.38/4.38=1.91\\\\z_2=(x_2-\mu)/\sigma=(123.5-120.12)/4.38=0.77\\\\\\P(x<128.5)-P(x<123.5)=P(z<1.91)-P(z<0.77)\\\\P(x<128.5)-P(x<123.5)=0.9719-0.7794=0.1925[/tex]

Triangle E F G. Side E F is 6 meters, F G is 5 meters, E G is 7 meters. Triangle K L J. Side K L is 28 meters, L J is 24 meters, J K is 20 meters. Given that these triangles are similar, which side corresponds to side GE? Given that these triangles are similar, which side corresponds to side JK?

Answers

The first one is KL and the second one is FG

Side GE corresponds to side EJ, which is 24 meters long and side JK corresponds to side LK, which is 60/7 meters (or approximately 8.57 meters) long.

What are Similar Triangles?

Two triangles are said to be similar if their corresponding angles are congruent and the corresponding sides are in proportion .

To determine which side of triangle EFG corresponds to side GE

we need to find the ratio of the lengths of corresponding sides.

The sides that share vertex E are EF and EJ, so we can write:

EF / EJ = FG / FJ = EG / EK

Substituting the given values, we get:

6 / ? = 5 / ? = 7 / 20

To solve for the missing value, we can cross-multiply and simplify:

6 × 20 = 5 × x

x = 24

To determine which side of triangle KLJ corresponds to side JK, we can use the same approach.

The sides that share vertex J are JL and JF, so we can write:

JL / JF = LK / EF = LJ / FG

Substituting the given values, we get:

24 / ? = 20 / 6 = 28 / 5

Cross-multiplying and simplifying:

24 × 5 = x × 28

x = 60 / 7

Therefore, side GE corresponds to side EJ, which is 24 meters long and side JK corresponds to side LK, which is 60/7 meters (or approximately 8.57 meters) long.

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(1 point) Let pp be the quartic (degree 4) polynomial that satisfies p(i)=2i,i=0,1,2,3,4. p(i)=2i,i=0,1,2,3,4. Then p(x)=p(x)= . Hint: You may have a better idea, but a brute force approach is to write p(x)=ax4+bx3+cx2+dx+e p(x)=ax4+bx3+cx2+dx+e where aa, bb, cc, dd, and ee, are the unknown coefficients, and then solve the linear system p(0)=1p(0)=1, p(1)=2p(1)=2, p(2)=4p(2)=4, p(3)=8p(3)=8, and p(4)=16p(4)=16 for aa, bb, cc, dd, and ee. Preview My AnswersSubmit Answers

Answers

Answer:

a = 1/3

b = -3

c = 26/3

d = -6

e = 0

Step-by-step explanation:

Given the quartic polynomial

p(x)=ax⁴+bx³+cx²+dx+e and

p(i) =2i when i=0,1,2,3,4

If i = 0:

p(0) = 2(0)

p(0) = 0

0 = 0+0+0+0+0++e

e = 0

When i = 1

p(1) = 2(1) = 2

2 = a(1)⁴+b(1)³+c(1)²+d(1)+e

2 = a+b+c+d+0

a+b+c+d = 0... (1)

When i = 2, p(2) = 2(2)

p(2) = 4

4 = a(2)⁴+b(2)³+c(2)²+d(2)+e

4 = 16a+8b+4c+2d+0

16a+8b+4c+2d = 4

8a+4b+2c+d = 2... (2)

When i = 3

p(3) = 8

8 = a(3)⁴+b(3)³+c(3)²+d(3)+0

8 = 81a+27b+9c+3d..(3)

When i = 4

p(4) =16

16 = a(4)⁴+b(4)³+c(4)²+d(4)+0

16 = 256a+64b+16c+4d

64a+16b+4c+d = 4...(4)

Solving equation 1 to 4 simultaneously.

Check the attachment for solution.

Final answer:

The problem here is to determine the coefficients of a quartic polynomial to match the given conditions. This results in a system of linear equations which can be solved to find the desired coefficients.

Explanation:

This question is a

polynomial problem

and involves finding the coefficients of a

quartic polynomial

, and for that we form a system of linear equations. Using the given conditions, we get the following equations:

For p(0), we get e = 2*0 = 0 For p(1), we get a + b + c + d + e = 2 For p(2), we get 16a + 8b + 4c + 2d + e = 4 For p(3), we get 81a + 27b + 9c + 3d + e = 6 For p(4), we get 256a + 64b + 16c + 4d + e = 8

By solving the above system of equations, we can find the values of a, b, c, d and e that satisfy those equations simultaneously.

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Suppose we want to assess the effect of a one-day SAT prep class at a 5% level of significance. Scores on the SAT writing exam can range from 200 to 800. A random sample of 50 students takes the SAT writing test before and after a prep class. We test the hypotheses: H 0: μ = 0 H a: μ > 0 where μ is the mean of the difference in SAT writing scores (after minus before) for all students who take the SAT prep class. The sample mean is 5 with a standard deviation of 18. Since the sample size is large, we are able to conduct the T-Test. The T-test statistic is approximately 1.96 with a P-value of approximately 0.028. What can we conclude? Group of answer choices The one-day SAT prep class is associated with statistically significant improvements in SAT writing performance. Students taking a one-day SAT prep class performed significantly better on the SAT writing exam than students who did not take the class. Students taking a one-day SAT prep class do not show statistically significant improvements in their SAT writing performance. Scores only increased by 5 points, which is not significant on an exam where scores can range from 200 to 800. The one-day SAT prep class produces statistically significant improvements in SAT writing performance.

Answers

Answer: The one-day SAT prep class is associated with statistically significant improvements in SAT writing performance.

Step-by-step explanation: just took the quiz

The correct conclusion about the situation is, the one-day SAT prep class produces statistically significant improvements in SAT writing performance, which is option (e).

Given that:

It is assessing the performance of the students in the SAT writing exam before and after SAT prep class.

The hypothesis is:

H₀: μ = 0

H₁: μ > 0

This is a one-tailed test.

Here, the T-test is used.

Now, the significance level is, α = 0.05

p-value = 0.028

Since, the p-value, 0.028 is less than the significance level 0.05, the null hypothesis is rejected.

So, the mean of the difference in SAT scores is greater than 0.

That is, there is a significant effect in SAT exam by the prep class.

Hence, the correct conclusion is, The one-day SAT prep class produces statistically significant improvements in SAT writing performance, which is option (e).

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Over 10 minutes ,how far on a clock does the tip of a 12 inch minute hand move ?
A: 2.09inches
B: 6.28 inches
C: 12.56 inches
D: 75.36 inches


Need help please anyone

Answers

Answer:

C: 12.56 inches

Step-by-step explanation:

We know that the minute hand can move an equivalent of 60 minutes in any one revolution.

-10 minutes movement is equal to 1/6 the total distance and the circumference covered in that time is calculated as:

[tex]C=\pi D\\\\=\frac{1}{6}\pi \times (12\times 2)\\\\\\=12.56\ in[/tex]

Hence, over 10 minutes the minutes hand moves 12.56 inches away.

Final answer:

The tip of a 12 inch minute hand will move approximately 12.56 inches over the course of 10 minutes, which aligns with option C in your given choices.

Explanation:

The subject of this question is Mathematics, specifically geometry and involves calculating the length of an arc within a circle. The minute hand of a clock can be thought of as the radius of a circle, with a full rotation of the hand representing a complete circle. The minute hand moves 360 degrees in 60 minutes (or 6 degrees per minute), so over 10 minutes, the minute hand will move 60 degrees.

Now, the length of that portion of the circle (the arc length) is calculated using the formula: (2πr)(θ/360), where r is the radius (half of the diameter, or 12 inches in this case), and θ is the angle in degrees. When you plug in the respective values, you will find that the minute hand of the clock moves an approximate distance of 12.56 inches, which corresponds to option C in your given choices.

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The bumper car ride at the state fair has 2 red cars, 4 green cars, an for the ride and is assigned a the probability that both events A and B occur. Express your answer your answer to the nearest tenth d 2 blue cars. Garth is first in line car at random. Patty is next in line and is randomly assigned a car. Find as a percent. If necessary, round

Event A: Garth will drive a red bumper car.
Event B: Patty will drive a red bumper car.

a. 6.3%
b. 25%
c. 96.4%
d. 3.6%.

Answers

Answer:

a)  3.6%

Step-by-step explanation:

The given question mixed up, below is the correct question:

The bumper car ride at the state fair has 2 red cars, 4 green cars, and 2 blue cars. Garth is first in line for the ride and is assigned a car at random.  Patty is next in line and is randomly assigned a car. Find the probability that both events A and B occur. Express your answer as a percent. If necessary, round your answer to the nearest tenth.

Calculation:

Given that the state fair has 2 red cars, 4 green cars and 2 blue cars.

There are therefore 2+4+2 = 8 cars in total.

Probability that Events A occurs P(A) = [tex]\frac{2}{8}[/tex] = 4

Probability that Events B occurs P(B) = [tex]\frac{1}{7}[/tex]

Probability that Events A and B occur P(A ∩ B) = [tex]\frac{2}{8}[/tex] × [tex]\frac{1}{7}[/tex] = [tex]\frac{2}{56}[/tex] = 0.0357 = 3.57%  ≈ 3.6%

Therefore, the probability that both events A and B occur is 3.6%

Final answer:

The probability that both Garth and Patty will drive a red bumper car is found by multiplying the probability of Garth picking a red car (1/4) by the probability of Patty picking a red car after Garth (1/7), resulting in 1/28 or approximately 3.6%.

Explanation:

To solve the problem, we need to calculate the probability that both events A and B happen, which involves Garth and Patty both getting a red bumper car. Initially, there are 2 red cars, 4 green cars, and 2 blue cars, totaling 8 cars.

Event A: Garth picks a red car. The probability of this happening is the number of red cars over the total number of cars. So P(A) = 2/8 = 1/4.

After Garth picks a red car, there is 1 red car, 4 green cars, and 2 blue cars left, totaling 7 cars.

Event B: Patty picks a red car after Garth has already picked one. The probability of this happening is the number of remaining red cars over the total number of remaining cars. So P(B after A) = 1/7.

The probability that both A and B occur is the product of the probability of A and the probability of B given A has occurred. So P(A and B) = P(A) × P(B after A) = (1/4) × (1/7).

P(A and B) = 1/28. To express this as a percent, we multiply by 100%: (1/28) × 100% ≈ 3.6%.

Therefore, the probability that both Garth and Patty will drive a red bumper car is approximately 3.6%, which corresponds to option d.

Given the following 3 vertices, F(-5,1), A(-2,5), C(6,-1), find the fourth vertex, E, to make the figure a rectangle. Prove that FACE is a rectangle.

Answers

Answer:

  E(3, -5)

Step-by-step explanation:

In a rectangle, the diagonals are the same length and bisect each other. That means their midpoints are the same. Then ...

  (F +C)/2 = (A +E)/2

  E = F +C -A

  E = (-5, 1) +(6, -1) -(-2, 5) = (-5+6+2, 1-1-5)

  E = (3, -5) . . . . . . . E is chosen so that the midpoint of AE is that of FC

__

To prove the figure is a rectangle, we can show the lengths of the diagonals are the same. Using the distance formula, ...

  FC = √((6-(-5))^2 +(-1-1)^2) = √(11^2 +2^2) = √125

  AE = √((3-(-2))^2 +(-5-5)^2) = √(5^2 +10^2) = √125

The diagonals are the same length and have the same midpoint, so the figure is a rectangle.

PLEASE CALCULUS HELP!!!!!!

Answers

Answer:

work and answer are shown in the picture

Step-by-step explanation:

if you have any questions about my work please let me know

In repeated samples, approximately 99% of all differences in sample means will fall within the bounds of the interval already computed.
a. True
b. False

Answers

Answer:

a) True

Step-by-step explanation:

Repeated samples are a type of samples that are used to determine the features or characteristics or a given set of data.

In repeated samples, statistical techniques are applied whereby two samples that have similar characteristics are tested or analysed under different conditions.

Repeated samples can also be called matched or paired samples.

In repeated samples , we have what we refer to as confidence intervals. These are intervals whereby the true and correct value of certain parameters such as mean, the standard deviation of a given data or distribution is determined. We have confidence interval levels of 90%, 95% and 99%.

In repeated samples, approximately 99% of all differences in sample means will fall within the bounds of the interval already computed.

When a car is first observed it has a speed of 20 ms-1. after a time of 10 S it is observed that the speed is 50 MS-1​

Answers

Answer:

i need points.

Step-by-step explanation:

A toolbox has 10 screwdrivers Sid 6 wrenches.
Bella puts 8 more wrenches in the toolbox.
*) How many more wrenches are in the toolbox
than screwdrivers?

Answers

Answer: There are 4 more wrenches in the toolbox then the screwdrivers.

Step-by-step explanation: Add the 6 wrenches Sid put in the toolbox with the 8 wrenches Bella added to get 14 wrenches in total. Then, subtract the 10 screwdrivers from the 14 wrenches to get 4 wrenches.

Final answer:

Bella added 8 wrenches to the toolbox, making a total of 14 wrenches. There were initially 10 screwdrivers, so there are now 4 more wrenches than screwdrivers.

Explanation:

Calculating the Difference Between Wrenches and Screwdrivers in a Toolbox

Initially, there are 10 screwdrivers and 6 wrenches in the toolbox. Bella adds 8 more wrenches, which brings the total number of wrenches to 6 + 8, which equals 14 wrenches. The question asks how many more wrenches there are than screwdrivers. To find this, we subtract the number of screwdrivers from the number of wrenches:

14 wrenches - 10 screwdrivers = 4 more wrenches than screwdrivers in the toolbox.

A psychological study found that men who were distance runners lived, on average, five years longer than those who were not distance runners. The study was conducted using a random sample of 50 men who were distance runners and an independent random sample of 30 men who were not distance runners. The men who were distance runners lived to be 84.2 years old, on average, with a standard deviation of 10.2 years. The men who were not distance runners lived to be 79.2 years old, on average, with a standard deviation of 6.8 years.
What is the test statistic for the appropriate test to determine if men who are distance runners live significantly longer, on average, than men who are not distance runners?

Answers

Answer: C

Step-by-step explanation:

Evaluate the function

Given f(x) = x^2-3x+2, find f(-2)

Answers

Answer:

f( - 2) =12

Step-by-step explanation:

[tex]f(x) = x^2-3x+2 \\ plugging \: x = - 2 \\ f( - 2) = ( - 2)^2-3( - 2)+2 \\ f( - 2) =4 + 6+2 \\ f( - 2) =12 \\ [/tex]

Last month, Bethany sent 5,450 texts. This month she sent 7,085 texts. What was the percent increase in her texting from last month to this month?

Answers

Answer:

Hello

The answer is  30% increase in texts since last month.

IF you feel any problem in understanding , do comment pls.

Step-by-step explanation:

Let

X = last month sent texts

y = this month sent texts

First of all find the no. of increased texts,

by subtracting x from y

=> y-x= 7085- 5450

        = 1635

We want to find these 15 texts % with respect to 5450 texts

i.e.    1635/X

=0.30

for answer in % multiply with 100

i.e. 30%

5. Oscar needs to fill a sphere-shaped balloon with
helium. If the balloon has a diameter of 8 inches, what is
the total amount of helium that the balloon will hold to
the nearest tenth?
A. 2,143.6 in.3
B. 714.5 in.
C. 268.1 in.3
D. 150.7 in.

Answers

Final answer:

Oscar's balloon, which has an 8-inch diameter, will hold approximately 268.1 cubic inches of helium, calculated using the volume formula for a sphere.

Explanation:

Oscar needs to calculate the volume of a sphere-shaped balloon to determine how much helium it can hold. To find the balloon's volume, we use the formula for the volume of a sphere, which is V = ⅓πd³, where V is the volume, π is approximately 3.14159, and d is the diameter of the sphere. Since the balloon has a diameter of 8 inches, its radius r is 4 inches (which is half of the diameter).

Plugging the radius into the formula, we get: V = ⅓π(4 inches)³ = ⅓π(64 inches³) = 268.0826 inches³. Therefore, Oscar's balloon will hold approximately 268.1 cubic inches of helium to the nearest tenth, making the correct answer C. 268.1 in.³

What is equivalent to 16 3/4x

Answers

Answer:

⁴ˣ√16³

Step-by-step explanation:

The equivalent to 16^(3/4x) is ⁴ˣ√16³. It reads, 4x root of 16 raised to the power of 3. 1/4x as an exponent means the 4x root of the base number. 3 as an exponent simply means that the base number is raised to the third power.

If 10 pounds of ice cream are separated into 15 bowls, how much ice cream would be in each bowl?

Answers

Answer:

2/3 of a pound.

Step-by-step explanation:

10 pounds per 15 bowls = 2 pounds per 3 bowls, this is equal to 2/3 of ice cream a pound in a single bowl.

A softball pitcher has a 0.487 probability of throwing a strike for each pitch. If the softball pitcher throws 29 pitches, what is the probability that no more than 14 of them are strikes?

Answers

Answer:

0.4801

Step-by-step explanation:

This is a binomial distribution question.

It can be approximated using normal distribution if the following conditions are met:

np > 10

n(1-p) > 10

Here,

n = 29

p = 0.487

So,

np = 14.12

n(1-p) = 14.88

So, we can use normal approximation here:

Binomial:  X ~ B(n,p)  becomes

Normal Approx:  X~ N([tex]np,\sqrt{np(1-p)}[/tex])

Mean is:

[tex]\mu=np=14.123[/tex]

Standard Deviation is:

[tex]\sigma=\sqrt{np(1-p)} =2.69[/tex]

We need probability of less than or equal to 14, so we can say:

P(x ≤ 14)

Using  [tex]z=\frac{x-\mu}{\sigma}[/tex], we have:

P(x ≤ 14) = [tex]P(\frac{x-\mu}{\sigma} \leq \frac{14-14.123}{2.69})\\=P(z \leq -0.05)\\=0.4801[/tex]

Note: We used z table in the last line

So the probability is 0.4801

Use the confidence level and sample data to find a confidence interval for estimating the population muμ. Round your answer to the same number of decimal places as the sample mean. A random sample of 9595 light bulbs had a mean life of x overbar equals 510x=510 hours with a standard deviation of sigma equals 37 hours.σ=37 hours. Construct a​ 90% confidence interval for the mean​ life, muμ​, of all light bulbs of this type.

Answers

Answer:= (504, 516)

Therefore, the 90% confidence interval (a,b) = ( 504, 516)

Step-by-step explanation:

Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.

The confidence interval of a statistical data can be written as.

x+/-zr/√n

Given that;

Mean gain x = 510

Standard deviation r = 37

Number of samples n = 95

Confidence interval = 90%

z(at 90% confidence) = 1.645

Substituting the values we have;

510+/-1.645(37/√95)

510+/-1.645(3.796)

510+/-6.24

510+/-6

= (504, 516)

Therefore at 90% confidence interval (a,b) = ( 504, 516)

A coin is tossed and a number cube is rolled what is the probability that the coin shows heads and the number cube shows six

Answers

Answer:

There is a 1/2 chance the coin will land on heads and there is a 1/6 chance that the number cube will land on 6. hope this helps

what is the 20th shape the pattern is triangle,circle,circle

Answers

Answer:

Circle

Step-by-step explanation:

I don't know if there is a more "professional" way to solve this, but I wrote out the pattern until I got to the twentieth shape and it ended up being a circle :)

Final answer:

The 20th shape in the pattern is a circle.

Explanation:

To determine the 20th shape in the pattern of triangle, circle, circle, we need to analyze the pattern. The pattern starts with a triangle and is followed by two circles. This sequence repeats - triangle, circle, circle. To find the 20th shape, we need to determine how many times this sequence repeats within the first 20 shapes. Each complete sequence consists of 3 shapes (triangle, circle, circle), so we divide 20 by 3 to get 6 complete sequences. The 6th complete sequence ends with a circle, so the 20th shape in the pattern is also a circle.

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The area of a triangle that is similar to the one below is the area of this triangle. What is the length of the base of the similar triangle? 2.3 ft 3.3 ft 7 ft 63 ft

Answers

The answer is 7 feet

Answer:

c. 7ft

good luck, i hope this helps :)

Need to solve
15,000,000 = 4700e 0.154t

Answers

t= 75000000/ 3619e.

Answer:

[tex]t=52.39[/tex]

Step-by-step explanation:

g Consider the following statement. For all sets A and B, (A − B) ∪ (A ∩ B) = A. Construct an algebraic proof for the statement. Cite a property from Theorem 6.2.2 for every step.

Answers

Final answer:

To prove the statement (A − B) ∪ (A ∩ B) = A, we can use the property of set difference, distribution, and identity from Theorem 6.2.2.

Explanation:

To construct an algebraic proof for the statement (A − B) ∪ (A ∩ B) = A, we can use the property of set difference, distribution, and identity from Theorem 6.2.2.

Start with the left side of the equation: (A − B) ∪ (A ∩ B)Apply the property of set difference: (A − B) = A ∩ B'. Now the equation becomes (A ∩ B') ∪ (A ∩ B).Use the property of distribution: A ∩ (B' ∪ B) = A ∩ U = A, where U represents the universal set. Therefore, (A − B) ∪ (A ∩ B) = A.

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Find the slope of the line that passes through the pair of points.

(5,-4) AND (9,-4)

USE THE SLOPE FORMULA

Answers

Answer:

  0

Step-by-step explanation:

The slope formula is ...

  m = (y2 -y1)/(x2 -x1)

Filling in the given point values, we find the slope to be ...

  m = (-4 -(-4))/(9 -5) = 0/4 = 0

The slope is 0.

_____

The y-values are the same at -4, the equation of the line is y = -4. It is a horizontal line with zero slope.

Bank of America's Consumer Spending Survey collected data on annual credit card charges in seven different categories of expenditures: transportation, groceries, dining out, household expenses, home furnishings, apparel, and entertainment. Using data from a sample of credit card accounts, assume that each account was used to identify the annual credit card charges for groceries (population 1) and the annual credit card charges for dining out (population 2). Using the difference data, the sample mean difference was , and the sample standard deviation was .

Answers

Answer:

a) Null hypothesis: [tex]\mu_d= 0[/tex]

Alternative hypothesis: [tex]\mu_d \neq 0[/tex]

b) [tex]t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=\frac{850 -0}{\frac{1123}{\sqrt{42}}}=4.905[/tex]

The next step is calculate the degrees of freedom given by:

[tex]df=n-1=42-1=41[/tex]

Now we can calculate the p value, since we have a left tailed test the p value is given by:

[tex]p_v =2*P(t_{(41)}>4.905) =0.000015[/tex]

So the p value is lower than any significance level given, so then we can conclude that we can reject the null hypothesis that the difference between he two groups are equal.

Step-by-step explanation:

Assuming the following questions:

We assume the following data: [tex] n = 42 ,\bar d= 850 , s_d = 1123[/tex]

Previous concepts

A paired t-test is used to compare two population means where you have two samples in  which observations in one sample can be paired with observations in the other sample. For example  if we have Before-and-after observations (This problem) we can use it.  

a. Formulate the null and alternative hypotheses to test for no difference between the population mean credit card charges for groceries and the population mean credit card charges for dining out.

The system of hypothesis for this case are:

Null hypothesis: [tex]\mu_2- \mu_1 = 0[/tex]

Alternative hypothesis: [tex]\mu_2 -\mu_1 \neq 0[/tex]

Or equivalently

Null hypothesis: [tex]\mu_d= 0[/tex]

Alternative hypothesis: [tex]\mu_d \neq 0[/tex]

b. Use a .05 level of significance. Can you conclude that the population means differ? What is the p-value?

[tex]t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=\frac{850 -0}{\frac{1123}{\sqrt{42}}}=4.905[/tex]

The next step is calculate the degrees of freedom given by:

[tex]df=n-1=42-1=41[/tex]

Now we can calculate the p value, since we have a left tailed test the p value is given by:

[tex]p_v =2*P(t_{(41)}>4.905) =0.000015[/tex]

So the p value is lower than any significance level given, so then we can conclude that we can reject the null hypothesis that the difference between he two groups are equal.

Help Fast Which transformations could have occurred to map △ABC to △A"B"C"? a rotation and a dilation a rotation and a reflection a reflection and a dilation a translation and a dilation

Answers

It probably a rotation and a dilation

Answer:

its A

Step-by-step explanation:

Figure ABCD is a square. Prove BD ≅ AC. Square A B C D with diagonals is shown. Statements Reasons 1. ABCD is a square 1. given 2. ∠DAB, ∠ABC, ∠BCD, and ∠CDA are right angles 2. definition of a square 3. ∠DAB ≅ ∠ABC ≅ ∠BCD ≅ ∠CDA 3. right angles are congruent 4. AB ≅ BC ≅ CD ≅ DA 4. ? 5. △BAD ≅ △ABC 5. SAS 6. BD ≅ AC 6. CPCTC What is the missing reason in the proof?
all sides of a square are congruent
all right angles measure 90°
definition of diagonal
definition of perpendicular

Answers

Answer:

all sides are congruent

Step-by-step explanation:

its talking about sides

I believe A is correct

Good luck!

Suppose ACT Reading scores are normally distributed with a mean of 21.3 and a standard deviation of 5.9. A university plans to award scholarships to students whose scores are in the top 7%. What is the minimum score required for the scholarship? Round your answer to the nearest tenth, if necessary.

Answers

Answer:

30.0

Step-by-step explanation:

Given our data is normally distribute with [tex]\mu=21.3[/tex] and [tex]\sigma=5.9[/tex]

-Top 7% is given by find the z-value corresponding to p=(1-0.07)=0.93

-We substitute our values in the equation below;

[tex]z=\frac{\bar X-\mu}{\sigma}\\\\\\=\frac{X-21.3}{5.9}, z_{0.035}=1.476\\\\\therefore 1.476=\frac{X-21.3}{5.9}\\\\X=5.9\times 1.476+21.3\\\\=30.0084\approx30.0[/tex]

Hence, the minimum score required for the scholarship is 30.0

The minimum ACT Reading score required for a university scholarship awarded to the top 7% is approximately 30.0.

To find the minimum ACT Reading score required for a scholarship awarded to students in the top 7%, we need to determine the z-score that corresponds to the top 7% of a normal distribution. We can then use this z-score to find the corresponding ACT score.

The z-score for the top 7% of a standard normal distribution is approximately 1.475. Since the ACT Reading scores have a mean (μ) of 21.3 and a standard deviation (σ) of 5.9, we can use the z-score formula to find the minimum score 'x' required for the scholarship: z = (x - μ) / σ.

Solving for 'x', we get: x = zσ + μ = 1.475(5.9) + 21.3 ≈ 30.0. Therefore, the minimum ACT Reading score required for the scholarship is approximately 30.0.

ΔWXY, the measure of ∠Y=90°, WY = 8, YX = 15, and XW = 17. What ratio represents the tangent of ∠X?

Answers

The ratio Tangent is the opposite side over the adjacent side of the angle.
Tan (x) = 8/15
Final answer:

In a right triangle, the tangent of an angle is defined as the ratio of the opposite side to the adjacent side. Therefore, for triangle ΔWXY, the tangent of ∠X is the ratio of side WY to YX, which is 8/15.

Explanation:

To understand this question, we need to know that in the context of a right triangle, the tangent of an angle is defined as the ratio of the length of the opposite side to the length of the adjacent side. In ΔWXY, where the measure of ∠Y=90°, ∠X is the angle we are considering. The side opposite to ∠X is WY and the side adjacent to ∠X is YX. Therefore, the tangent of ∠X can be calculated using the formula: tan(X) = WY / YX.

In this scenario, we know that WY = 8 and YX = 15. So, the tangent of ∠X is given by: tan(X) = WY / YX = 8 / 15. Hence, the ratio that represents the tangent of ∠X is 8 / 15.

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