Explain what "statistical significance" means. Choose the correct explanation below. A. Statistical significance means that the tools used to measure the data introduce error that needs to be accounted for when considering whether or not to reject the null hypothesis. B. Statistical significance means that the sample standard deviation is unusually small, resulting in an unusually large test statistic. C. Statistical significance means that the null hypothesis claims the population proportion is equal to something other than 0.5. D. Statistical significance means that the result observed in a sample is unusual when the null hypothesis is assumed to be true. E. Statistical significance means that the scenario being analyzed will have a meaningful real-world impact.
Answer:
The correct explanation is:
D. Statistical significance means that the result observed in a sample is unusual when the null hypothesis is assumed to be true.
Step-by-step explanation:
The statistical significance gives a threshold to measure if a sample result or observed effect is due only to a sampling or it really reflects a characteristics of the population we are studying.
The level of statistical significance is usually 0.05 or 5%, depending on how strong the evidence needs to be and the consequences of the conclusions of the study, taking into account the Type I and Type II errors.
The statistical significance provides a cutoff point for determining whether a sampling outcome, as well as observable impact, is attributable mostly to screening whether accurately reflects features of the target population under investigation.The threshold of such significance is very often 0.05 as well as 5%, on whatever the documentation has to be because the implications of the study's results, recognize the importance of Type I as well as the Type II mistakes.
Thus the response above i.e., "option D" is appropriate.
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Pat needs to determine the height of a tree before cutting it down to be sure that it will not fall on a nearby fence. The angle of elevation of the tree from one position on a flat path from the tree is Upper H equals 60 degrees comma and from a second position Upper L equals 60 feet farther along this path it is Upper B equals 50 degrees . What is the height of the tree?
Answer:
229.23 feet.
Step-by-step explanation:
The pictorial representation of the problem is attached herewith.
Our goal is to determine the height, h of the tree in the right triangle given.
In Triangle BOH
[tex]Tan 60^0=\dfrac{h}{x}\\h=xTan 60^0[/tex]
Similarly, In Triangle BOL
[tex]Tan 50^0=\dfrac{h}{x+60}\\h=(x+60)Tan 50^0[/tex]
Equating the Value of h
[tex]xTan 60^0=(x+60)Tan 50^0\\xTan 60^0=xTan 50^0+60Tan 50^0\\xTan 60^0-xTan 50^0=60Tan 50^0\\x(Tan 60^0-Tan 50^0)=60Tan 50^0\\x=\dfrac{60Tan 50^0}{Tan 60^0-Tan 50^0} ft[/tex]
Since we have found the value of x, we can now determine the height, h of the tree.
[tex]h=\left(\dfrac{60Tan 50^0}{Tan 60^0-Tan 50^0}\right)\cdotTan 60^0\\h=229.23 feet[/tex]
The height of the tree is 229.23 feet.
32) In one region, the September energy consumption levels for single-family homes are found to be normally distributed with a mean of 990 kWh and a standard deviation of 198 kWh. For a randomly selected home, find the probability that the September energy consumption level is between 1100 kWh and 1250 kWh.
Answer:
0.1946 is the probability that the September energy consumption level is between 1100 kWh and 1250 kWh.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 990 kWh
Standard Deviation, σ = 198 kWh
We are given that the distribution of energy consumption levels is a bell shaped distribution that is a normal distribution.
Formula:
[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]
P(September energy consumption level is between 1100 kWh and 1250 kWh)
[tex]P(1100 \leq x \leq 1250)\\\\ = P(\displaystyle\frac{1100 - 990}{198} \leq z \leq \displaystyle\frac{1250 -990}{198}) \\\\= P(0.5556 \leq z \leq 1.3131)\\\\= P(z \leq 1.3131) - P(z < 0.5556)\\\\= 0.9054- 0.7108= 0.1946[/tex]
0.1946 is the probability that the September energy consumption level is between 1100 kWh and 1250 kWh.
Convert 3/7 into a percent.
Answer:
42.86%
Step-by-step explanation:
3/7 as a decimal is 0.4286... and to convert that into a decimal, you move the decimal point right twice.
0.4286 = 42.86%
I hope this helped!
Final answer:
To convert the fraction 3/7 into a percent, divide 3 by 7 to get the decimal 0.4286, then multiply by 100 to get 42.86%.
Explanation:
Converting a Fraction to a Percent
To convert a fraction like 3/7 into a percent, follow these steps:
Convert the fraction to a decimal by dividing the numerator by the denominator. For 3/7, divide 3 by 7 to get approximately 0.4286.Convert the decimal to a percent by multiplying it by 100. So, 0.4286 times 100 equals 42.86.Therefore, 3/7 as a percent is 42.86%.
A percent (or per cent) is a way of expressing a number as a fraction of 100. The term "percent" comes from the Latin per centum, which means "by the hundred." It is often represented by the symbol "%."
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
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.
The manager of a fund that provides loans for college students has estimated that the average monthly loan repayment for students borrowing from the fund is $75.00. You are to test this estimate. You take a sample of 20 students and find that the mean monthly payment is $69.46 with a standard deviation of $9.78. Which of the following statements is true about this test?
a. The value of the test statistic is -.57; therefore, the null hypothesis is rejected for mean = 0.02.
b. The value of the test statistic is -2.53; therefore, the null hypothesis is rejected for mean = 0.02.
c. The value of the test statistic is -2.53; therefore, the null hypothesis is rejected for mean = 0.05 but not for mean = 0.02.
d. The value of the test statistic is -.57; therefore, the null hypothesis is rejected for mean = 0.05 but not for mean = 0.02.
Answer:
Step-by-step explanation:
We would set up the hypothesis test.
For the null hypothesis,
µ = 75
For the alternative hypothesis,
µ ≠ 75
Since the number of samples is 20 and no population standard deviation is given, the distribution is a student's t.
Since n = 20,
Degrees of freedom, df = n - 1 = 20 - 1 = 19
t = (x - µ)/(s/√n)
Where
x = sample mean = $69.46
µ = population mean = $75
s = samples standard deviation = $9.78
t = (69.46 - 75)/(9.78/√20) = - 2.53
We would determine the p value using the t test calculator. It becomes
p = 0.01
Since alpha, 0.05 > than the p value, 0.01, then the null hypothesis is rejected.
Therefore,
The value of the test statistic is -2.53; therefore, the null hypothesis is rejected for level of significance = 0.05
A triangle is drawn on the coordinate plane. It is translated 4 units right and 3 units down. Which rule describes the
translation?
(x, y) - (x + 3, y - 4)
(x,y) → (x + 3, y + 4)
(x, y) - (x +4, Y-3)
(x, y) (x + 4, y + 3)
Answer:
C
Step-by-step explanation:
The correct option is option C , that is the rule which describes the translation is (x, y) → (x + 4, y - 3).
What do you mean by translation ?
The modification of an existing diagram to create a different version of the following diagram is known as translation.
The translated triangle is moved along the x-axis by 4 units, to the right. The numbers get more positive as one moves to the right along the x-axis, hence an additional 4 units should be added to the x-coordinate. So , the coordinate would be x + 4.
Along the y-axis, the triangle is also pushed downward by 3 units. More negative numbers are produced as the axis moves below, hence 3 should be subtracted. So , the coordinate should be y - 3.
Based on the above information, we can conclude that another way to write the given rule by translation is (x, y) → (x + 4, y - 3) .
Therefore , the correct option is option C , that is the rule which describes the translation is (x, y) → (x + 4, y - 3).
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Consider the following time series: t sales 1 6 2 11 3 9 4 16 5 17 Use simple linear regression analysis with t as the predictor variable to find the parameters for the line that minimizes MSE for this time series. Enter the data into Excel and use Excel for your calculations. Enter the exact answers. a) y-intercept, b0 = -0.67 b) slope, b1 = 0.31 What is the MSE if this model is used to forecast sales for time periods 1-5? c) MSE = What is the forecast for time period t = 6?\
Answer:
Check the explanation
Step-by-step explanation:
Period, X Actual , Y
1 6
2 11
3 9
4 16
5 17
Y= intercept + slope*x
Answer a and b:
INTERCEPT(known Y's,known X's) Slope(known Y's,known X's)
3.7 2.7
Simple linear regression equation is
Forecast, Y= 3.7+ 2.7*x
Period, X Actual , Y linear Absolute squared
trend deviation= deviation=
Forecast, |Forecast - (absolute
Y= 3.7+ 2.7*x Actual| deviation)^2
1 6 6.40 0.4 0.2
2 11 9.10 1.9 3.6
3 9 11.80 2.8 7.8
4 16 14.50 1.5 2.3
5 17 17.20 0.2 0.0
6 19.90
2.78
MSE
Answer c: MSE= 2.78
Answer d: Forecast for x= 6= 19.90
4. For the vectors b = (1, 2, −2) and a = (−3, 0, 4) (a) Compute the projection of vector b onto the line along vector a as p = ˆxa. (b) Compute the projection of vector b onto the line along vector a as p = Pb. (c) Compute the error vector. (d) Compute the length of the projection vector and length of the error vector.
Answer:
A) (33/5, 0, 44/5)
B) - 11
C) (28/5, 2, - 54/5)
D) 11, 12.83
Step-by-step explanation:
A)
Given the vectors
b= (1, 2,-2)
a= (-3, 0, 4)
Projection of the vector b onto the line along vector a as p=ˆxa
Calculating ab,
ab= a1b1 + a2b2 + a3b3
a1= - 3, a2=0, a3=4, b1=1, b2=2, b3= - 2
ab= (-3)(1) + (0)(2) +(4)(-2)
ab= - 3 + 0 +(-8)
ab= - 11
Vector projection which is
( ab÷ /vector a/^2) × vector a
= - 11/√(-3)^2 + (0)^2 + (4)^2
= - 11/ √9 +16
=-11/√25
= - 11/5× (-3, 0, - 4)
= (33/5, 0, 44/5)
B) When p= pb
It will be a scalar projection and will be written as:
ab÷ /a/
-11/√1
= - 11
C) Given the vector that form P to b in
e= b - p
=b- ˆxa
e= (1, 2,-2) - (33/5, 0, 44/5)
= (1 - 33/5, 2- 0, -2 - 44/5)
=(5-33/5, 2, - 10- 44/5)
= (28/5, 2, - 54/5)
D.
Length of the projection vector:
/e/ = √(33/5^2 + 0 + 44/5^2)
/e/= √33^2/25 + 0 + 44^2/25
/e/= √33^2/25 +44^2/25
/e/= √121
/e/= 11
Length of error vector
/e/ = √(28/5)^2 + 2^2 + (-54/5)^2
/e/= √28^2/25 +4 +(-54^2/25)
/e/= 12.83
Answer:
a) and b) p= (33/25, 0, -44/25)
c) e = (-8/25, 2, -6/25)
d) p = 11/5 = 2.2
e) e = (2/5)√26 = 2.039
Step-by-step explanation:
Given
b = (1, 2, −2)
a = (−3, 0, 4)
a) and b) We use the formula
p = (at*b)/(at*a)*a
⇒ p = ((−3, 0, 4)*(1, 2, −2)/((−3, 0, 4)*(−3, 0, 4)))*(−3, 0, 4)
[tex]p=\frac{at*b}{at*a}*a\\ p=\frac{(-3, 0, 4)*(1, 2,-2)}{(-3, 0, 4)*(-3, 0, 4)} *(-3, 0, 4)\\ p=\frac{-3+0-8}{9+0+16}*(-3, 0, 4)\\ p=-\frac{11}{25} *(-3, 0, 4)\\ p=(\frac{33}{25} ,0,-\frac{44}{25})[/tex]
c)
[tex]e=b-p\\ e=(1, 2, -2)-(\frac{33}{25} ,0,-\frac{44}{25})\\ e=(-\frac{8}{25} ,2,-\frac{6}{25} )[/tex]
d) We use the formula
[tex]p=\sqrt{(\frac{33}{25} )^{2} +(0)^{2} +(\frac{-44}{25} )^{2}} =\frac{11}{5}[/tex]
e) Applying the same formula we have
[tex]e=\sqrt{(\frac{-8}{25} )^{2} +(2)^{2} +(\frac{-6}{25} )^{2}} =\frac{2}{5}\sqrt{26} =2.039[/tex]
A cognitive psychologist wants to investigate whether memory for a shopping list is affected by the strategy used to study the list. She selects 20 random students and assigns each of them randomly to one of four different groups. Each group is given a different strategy by which to study the list. After the students study the list, they try to recall as many items as they can. The number of items remembered from the list for each students is given below.
Is there sufficient evidence to conclude that different strategies lead to different memory performance? Use significance level 0.05
Answer:
There is no sufficient evidence
Step-by-step explanation:
See attached files
How do I find A’?
Let U={a,b,c,d,e,f,g} and A={a,b,e,f}
Let U={a,b,c,d,e,f,g,h}
A={a,c,d}
B={b,c,d}
C={b,e,f,g,h}
Write each vector as a linear combination of the vectors in S. (If not possible, enter IMPOSSIBLE.) S = {(6, −7, 8, 6), (4, 6, −4, 1)} (a) u = (2, 19, −16, −4) u = −1 s1 + 2 s2 (b) v = 43 2 , 113 4 , −18, 13 2
Answer:
a) Yes, it is a linear combination.
b) Impossible to write as a linear combination.
Step-by-step explanation:
Recall that given vectors u,v,w we say that w is a linear combination of u and v if there exists real numbers a,b such that
[tex]w=au+bv[/tex]
a) [tex] u = (2,19,-16, -4)[/tex]. So, we have the following
[tex] (2,19,-16, -4)=a(6,-7,8,6)+b(4,6,-4,1)[/tex]. Which give us the following equations
[tex]6a+4b = 2[/tex]
[tex]-7a+6b = 19[/tex]
[tex]8a-4b = -16[/tex]
[tex]6a+b =-4[/tex]
Note that if we add the first and the third equation, we get that [tex]14a = -14[/tex] which implies that a=-1. In the first equation, if a=-1, then [tex]4b=2+6[/tex] which implies that b=2. We must check that when (a,b) =(-1,2) the four equations are still valid.
So
[tex]6(-1)+4(2) = -6+8 = 2[/tex]
[tex]-7(-1)+6(2) = 7+12 = 19[/tex]
[tex]8(-1)-4(2) = -8-8 = -16[/tex]
[tex]6(-1)+(2) =-6+2 = -4[/tex]
Since all equations are met, we have written the desired vector u as the linear combination of the initial vectors.
b) Repeating the same analysis, we get
[tex](432 , 1134 , −18, 132)=a(6,-7,8,6)+b(4,6,-4,1)[/tex]
[tex]6a+4b = 432[/tex]
[tex]-7a+6b = 1134[/tex]
[tex]8a-4b = -18[/tex]
[tex]6a+b =132[/tex]
adding the first and third equation we get [tex]14a = 414[/tex] so a = 207/7. Replacing this value will give us that b=891/14.
However,
note that
[tex]-7\frac{207}{7}+6\frac{891}{14} = \frac{1124}{7}\neq 1134[/tex]. Then, it is impossible to write the linear combination.
The question seeks a linear combination of vectors from a given set 'S' that matches specified vectors. Using vector addition and scalar multiplication, it is possible to find a unique combination for each specified vector. If no combination can provide the required vector, 'IMPOSSIBLE' is the answer.
Explanation:In this problem, you're asked to express a given vector as a linear combination of other vectors from the set 'S'. This involves using the properties of vector addition and scalar multiplication to define a unique way to represent each given vector. A linear combination of vectors involves adding or subtracting multiples of these vectors.
For instance, if we have the set S = {(6, -7, 8, 6), (4, 6, -4, 1)}, and we're asked to write the vector u = (2, 19, -16, -4), the correct linear combination would be -1 times the first vector in S plus 2 times the second vector (-1*(6,-7,8,6) + 2*(4,6,-4,1) = (2, 19, -16, -4)). This means vector 'u' would be expressed as u = -1 * S1 + 2 * S2. If no such combination is possible, the answer would be 'IMPOSSIBLE'.
Other important concepts related to this problem include vector addition, scalar multiplication, and the distributive property. Vector addition is both associative and commutative and vector multiplication by a sum of scalars is distributive. The direction and magnitude of vectors are also significant elements to consider while solving such problems.
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What is the v?
-18 - 3/4v = 3
Step-by-step explanation:
[tex] - 18 - \frac{3}{4v} = 3[/tex]
[tex] - \frac{3}{4v} = 3 + 18[/tex]
[tex] - \frac{3}{4v} = 21[/tex]
Now doing cross multiply
-3 = 21 * 4v
[tex]v = - \frac{3}{21 \times 4} [/tex]
Therefore
[tex]v \: = \frac{1}{28} [/tex]
Hope this helps.
We want to find the maximum and minimum values of f(x,y)=12x2+13y2 on the disk D: x2+y2≤1. What is the critical point in D? (x,y)=( , ) Now focus on the boundary of D, and solve for y2. Restricting f(x,y) to this boundary, we can express f(x,y) as a function of a single variable x. What is this function and its closed interval domain? f(x,y)=f(x)= where ≤x≤ What are the absolute maximum and minimum values of the function along the BOUNDARY of D? maximum value: minimum value: What are the absolute maximum and minimum values of f(x,y) over all of D? maximum value: minimum value:
Answer:
Over the boundary: maximum:13, minimum:12
Over D: maximum:13, minimum:0
Step-by-step explanation:
We are given that [tex]f(x,y) = 12x^2+13y^2[/tex] and D is the disc of radius one. Namely, [tex]x^2+y^2\leq 1[/tex].
First, we want to find a critical point of the function f. To do so, we want to find the values(x,y) such that
[tex] \nabla f (x,y) =0[/tex].
Recall that [tex] \nabla f (x,y) = (\frac{\partial f}{\partial x}, \frac{\partial f}{\partial y})[/tex].
So, let us calculate [tex] \nabla f (x,y)[/tex] (the detailed calculation of the derivatives is beyond the scope of the answer.
[tex]\frac{\partial f}{\partial x} = 24x[/tex]
[tex]\frac{\partial f}{\partial y} = 26y[/tex]
When equalling it to 0, we get that the critical point is (0,0), which is in our region D. Note that the function f is the sum of the square of two real numbers multiplied by some constants. Hence, the function f fulfills that [tex]f(x,y)\geq 0[/tex]. Note that f(0,0)=0, so without further analysis we know that the point (0,0) is a minimum of f over D.
If we restrict to the boundary, we have the following equation [tex] x^2+y^2=1[/tex]. Main idea is to replace the value of one of the variables n the function f, so it becomes a function of a single variable. Then, we can find the critical values by using differential calculus:
Case 1:
Let us replace y. So, we have that [tex]y^2=1-x^2[/tex]. So, [tex]f(x,y) = 12x^2+13(1-x^2) = -x^2+13[/tex].
So, we will find the derivative with respect to x and find the critical values. That is
[tex] \frac{df}{dx} = -2x=0[/tex]
Which implies that x =0. Then, [tex] y =\pm 1[/tex]. So we have the following critical points (0,1), (0,-1). Notice that for both points, the value of f is f(0,1) = f(0,-1) = 13. If we calculate the second derivative, we have that at x=0
[tex] \frac{d^2f}{dx^2} = -2<0[/tex]. By the second derivative criteria, we know that this points are local maximums of the function f.
Case 2:
Let us replace x. So, we have that [tex]x^2=1-y^2[/tex]. So, [tex]f(x,y) = 12(1-y^2)+13y^2 = y^2+12[/tex].
So, we will find the derivative with respect to y and find the critical values. That is
[tex] \frac{df}{dx} = 2y=0[/tex]
Which implies that y =0. Then, [tex] x =\pm 1[/tex]. So we have the following critical points (-1,0), (1,0). Notice that for both points, the value of f is f(1,0) = f(-1,0) = 12. If we calculate the second derivative, we have that at y=0
[tex] \frac{d^2f}{dx^2} = 2>0[/tex]. By the second derivative criteria, we know that this points are local minimums of the function f.
So, over the boundary D, the maximum value of f is 13 and the minimum value is 12. Over all D, the maximum value of f is 13 and the minimum value is 0.
Final answer:
The critical point of f(x, y) on the disk D is (0, 0). f(x) restricted to the boundary of D is f(x) = 12x^2 + 13(1 - x^2) with the domain [-1, 1]. The absolute maximum and minimum values of f(x, y) over all of D are 25 and 0, respectively.
Explanation:
To find the critical point of the function f(x, y) = 12x2 + 13y2 on the disk D: x2+y2 ≤ 1, we need to set the partial derivatives of f with respect to x and y equal to zero.
The partial derivative with respect to x is 24x, and setting it to zero gives x = 0. Similarly, the partial derivative with respect to y is 26y, which implies y = 0. Therefore, the critical point is (0, 0).
On the boundary of D, where x2+y2 = 1, we can solve for y2 as y2 = 1 - x2. Substituting into f, we get a function of a single variable x: f(x) = 12x2 + 13(1 - x2) with the closed interval domain [-1, 1].
The maximum value on the boundary occurs at x = ±1, giving a maximum of f(±1) = 25. The minimum on the boundary is at x = 0, which gives f(0) = 13.
Across the entire disk D, the absolute minimum is at the critical point (0,0), with f(0, 0) = 0, and the absolute maximum is the same as the boundary maximum, f(x) = 25.
Anne is a tailor and decides to evaluate her business to target potential customers with advertisements. She found that for every 12 women's dresses she alters, she alters 54 men's suits. Write this as a ratio in its simplest form.
Answer:
2/9
Step-by-step explanation:
The ratio is 12/54 which can be simplified by dividing the numerator and denominator by 6 to get 2/9
Making handcrafted pottery usually takes two major steps:wheel throwing and firing. The time of wheel throwing and thetime of firing are normally distributed random variables with meansof 40 min and 60 min and standard deviations of 2 min. and 3 min,respectively.
(a) What is the probability that a piece of pottery will befinished within 95 minutes?
(b) What is the probability that it will take longer than 110minutes?
Answer:
a) [tex]P(R<95)=P(\frac{R-\mu}{\sigma}<\frac{95-\mu}{\sigma})=P(Z<\frac{95-100}{3.606})=P(Z<-1.387)[/tex]
And we can find this probability using the normal standard table or excel and we got:
[tex]P(z<-1.387)=0.0827[/tex]
b) [tex]P(R>110)=P(\frac{R-\mu}{\sigma}>\frac{110-\mu}{\sigma})=P(Z>\frac{110-100}{3.606})=P(Z>2.774)[/tex]
And we can find this probability using the complement rule and the normal standard table or excel and we got:
[tex]P(z>2.774)=1-P(Z<2.774) = 1-0.9972 = 0.0028[/tex]
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Part a
Let X the random variable that represent the time for the step 1 and Y the time for the step 2, we define the random variable R= X+Y for the total time and the distribution for R assuming independence between X and Y is:
[tex]R \sim N(40+60 = 100,\sqrt{2^2 +3^2}= 3.606 s)[/tex]
Where [tex]\mu=65.5[/tex] and [tex]\sigma=2.6[/tex]
We are interested on this probability
[tex]P(R<95)[/tex]
And the best way to solve this problem is using the normal standard distribution and the z score given by:
[tex]z=\frac{R-\mu}{\sigma}[/tex]
If we apply this formula to our probability we got this:
[tex]P(R<95)=P(\frac{R-\mu}{\sigma}<\frac{95-\mu}{\sigma})=P(Z<\frac{95-100}{3.606})=P(Z<-1.387)[/tex]
And we can find this probability using the normal standard table or excel and we got:
[tex]P(z<-1.387)=0.0827[/tex]
Part b
[tex]P(R>110)=P(\frac{R-\mu}{\sigma}>\frac{110-\mu}{\sigma})=P(Z>\frac{110-100}{3.606})=P(Z>2.774)[/tex]
And we can find this probability using the complement rule and the normal standard table or excel and we got:
[tex]P(z>2.774)=1-P(Z<2.774) = 1-0.9972 = 0.0028[/tex]
Given Information:
Mean = μ = 40 + 60 = 100 minutes
Standard deviation = σ = 2² + 3² = 13 minutes
Required Information:
a. P(X < 95) = ?
b. P(X > 110) = ?
Answer:
a. P(X < 95) = 0.0823
b. P(X > 110) = 0 .0028
Explanation:
a)
Let random variable X represents the time in minutes of wheel throwing and firing.
The probability that a piece of pottery will be finished within 95 minutes means,
P(X < 95) = P(Z < (x - μ)/√σ)
P(X < 95) = P(Z < (95 - 100)/√13)
P(X < 95) = P(Z < -1.39)
The z-score corresponding to -1.39 is 0.0823
P(X < 95) = 0.0823
Therefore, there is 8.23% probability that a piece of pottery will be finished within 95 minutes.
b)
P(X > 110) = 1 - P(X < 110)
P(X > 110) = 1 - P(X < (x - μ)/√σ)
P(X > 110) = 1 - P(X < (110 - 100)/√13)
P(X > 110) = 1 - P(X < 2.77)
The z-score corresponding to 2.77 is 0.9972
P(X > 110) = 1 - 0.9972
P(X > 110) = 0 .0028
Therefore, there is 0.28% probability that a piece of pottery will take longer than 110 minutes.
You measure 40 watermelons' weights, and find they have a mean weight of 66 ounces. Assume the population standard deviation is 13.3 ounces. Based on this, what is the maximal margin of error associated with a 90% confidence interval for the true population mean watermelon weight.
Answer:
The maximal margin of error associated with a 90% confidence interval for the true population mean watermelon weight is of 3.46 ounces.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1-0.9}{2} = 0.05[/tex]
Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].
So it is z with a pvalue of [tex]1-0.05 = 0.95[/tex], so [tex]z = 1.645[/tex]
Now, find the margin of error M as such
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
In this problem:
[tex]\sigma = 13.3, n = 40[/tex]
So
[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]
[tex]M = 1.645*\frac{13.3}{\sqrt{40}}[/tex]
[tex]M = 3.46[/tex]
The maximal margin of error associated with a 90% confidence interval for the true population mean watermelon weight is of 3.46 ounces.
Final answer:
The maximal margin of error for a 90% confidence interval for the mean watermelon weight is calculated using the z-score for the confidence level, the known population standard deviation, and the sample size, resulting in 3.463 ounces.
Explanation:
To find the maximal margin of error associated with a 90% confidence interval for the true population mean watermelon weight when the mean weight of the watermelons is 66 ounces, the population standard deviation is 13.3 ounces, and the sample size is 40, we use the formula for the margin of error E = z * (σ / sqrt(n)), where z is the z-score corresponding to the confidence level, σ is the population standard deviation, and n is the sample size.
For a 90% confidence interval, the z-score is approximately 1.645. Plugging in the values, we get:
E = 1.645 * (13.3 / sqrt(40))
= 1.645 * (2.105)
= 3.463 ounces.
The maximal margin of error is therefore 3.463 ounces, which means the interval is 66 ± 3.463 ounces for the true population mean weight of watermelons with 90% confidence.
A toilet manufacturer has decided to come out with a new and improved toilet. The fixed cost for the production of this new toilet line is $16,600 and the variable costs are $63 per toilet. The company expects to sell the toilets for $160. Formulate a function C(x) for the total cost of producing x new toilets and a function R(x) for the total revenue generated from the sales of x toilets. How many toilets need to be sold to break even?
Answer:
C(x)=16600+63x
R(x)=160x
Break-even Point, x=172
Step-by-step explanation:
Let x be the number of Toilets Produced.
Fixed cost = $16,600
Variable costs = $63 per toilet.
Total Cost, C(x)=16600+63x
The company expects to sell the toilets for $160.
Selling Price Per Toilet=160
Total Revenue for x Toilets, R(x)=160x
Next, we determine the break-even point.
The break-even point is the point where the Cost of Production equals Revenue generated.
i.e. C(x)=R(x)
16600+63x=160x
16600=160x-63x
16600=97x
x=171.13
The company needs to sell at least 172 Toilets to break even.
To formulate the functions C(x) and R(x) for the total cost and revenue of producing and selling x toilets, we can use the given information about fixed costs, variable costs, and selling price. By setting the total cost equal to the total revenue, we can find the number of toilets needed to break even, which is approximately 171.
Explanation:To formulate the function C(x) for the total cost of producing x new toilets, we need to consider the fixed cost and the variable cost. The fixed cost is $16,600, which remains constant regardless of the number of toilets produced. The variable cost is $63 per toilet, so we multiply it by x to account for the number of toilets produced. Therefore, the function C(x) can be expressed as:
C(x) = 16,600 + 63x
The function R(x) for the total revenue generated from the sales of x toilets can be found by multiplying the selling price of each toilet by the number of toilets sold. Since each toilet is sold for $160, the function is:
R(x) = 160x
To find the number of toilets needed to break even, we need to determine the value of x when the total cost is equal to the total revenue. In other words, we set C(x) = R(x) and solve for x:
16,600 + 63x = 160x
Subtracting 63x from both sides:
16,600 = 97x
Dividing both sides by 97:
x = 170.10
Therefore, the company needs to sell approximately 171 toilets to break even.
Learn more about Functions here:https://brainly.com/question/35114770
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Please help me 3/4 - minus 5/12
Answer:
1/3
Step-by-step explanation:
For the 1st fraction, since 4 × 3 = 12,
3 /4 = 3 × 3/ 4 × 3 = 9/ 12
Likewise, for the 2nd fraction, since 12 × 1 = 12,
5 /12 = 5 × 1 /12 × 1 = 5 /12
Subtract the two fractions: 9 /12 - 5 /12 = 9 - 5 /12 = 4 /12
So next you simplify the answer how many 4 go in 4 and how many go in 12 the simplified answer is the answer is 1/3
Hope this helps
What Is The Area Of The Trapezoid
Answer:
256 m2
Step-by-step explanation:
- First, know the formula A = (a+b/2)h
- Using this, we will fill the equation in with our variables. For example...
A = ((13+19)/2)16
A = (32/2)16
A = (16)(16)
A = 256 m2
- Hope this helps! If you need a further explanation or step by step practice please let me know.
Which rational function models the time, y, in hours, that it takes the train to travel between the two cities at an average speed of x miles per hour?
y= x/6.4
y= x/160
y= 6.4/x
y= 160/x
Answer:
[tex]y=\frac{x}{6.4}[/tex]
Step-by-step explanation:
The complete question in the attached figure
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form [tex]k=\frac{y}{x}[/tex] or [tex]y=kx[/tex]
In this problem, we have a proportional relationship between the average speed (x) and the time (y)
Find the constant of proportionality k
Fox =32, y=5
[tex]k=\frac{5}{32}[/tex]
substitute
[tex]y=\frac{5}{32}x[/tex]
we have
[tex]\frac{5}{32}=\frac{1}{6.4}[/tex]
therefore
[tex]y=\frac{x}{6.4}[/tex]
A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 411 gram setting. It is believed that the machine is underfilling the bags. A 26 bag sample had a mean of 406 grams with a variance of 225. Assume the population is normally distributed. A level of significance of 0.02 will be used. Find the P-value of the test statistic. You may write the P-value as a range using interval notation, or as a decimal value rounded to four decimal places.
Answer:
0.0445937
Step-by-step explanation:
-Given that the sample statistic has a mean of 406 grams, standard deviation of sq root(225) and the null statistic is 411 grams.
-Assuming normal distribution, the test statistic is calculated as:
[tex]z=\frac{Sample \ statistic-Null \ statistic}{\sigma/\sqrt{n}}\\\\=\frac{406-411}{\sqrt{225/26}}\\\\=-1.6997[/tex]
-we then find the p-value of the test statistic from the z-tables:
P-value=0.0445937
A cell phone company wants to determine if the use of text messaging is independent of age. The following data has been collected from a random sample of customers. Regularly use text messaging Do not regularly use text messaging Under 21 82 38 21-39 57 34 40 and over 6 83 Based on the data above what is the expected value for the "under 21 and regularly use text messaging" cell? Question 5 options: 58 120 50 82
Answer:
Hi Gabbie,
The answer to your question that was what is the expected value for the "under 21 and regularly use text messaging" cell is 82.
Please rate me good :)
Step-by-step explanation:
The answer is 82 because the table that clearly defines the result was in the question.
Experts have predicted that approximately 1 in 12 tractor-trailer units will be involved in an accident this year. One reason for this is that 1 in 3 tractor-trailer units has an imminently hazardous mechanical condition, probably related to the braking systems on the vehicle.
1. If you wanted to calculate a 99% confidence interval that is no wider than 0.06, how many tractor-trailers would you need to sample?
2. Suppose a sample of 124 tractor-trailers is taken and that 45 of them are found to have a potentially serious braking system problem. Find a 90% confidence interval for the true proportion of all tractor-trailers that have this potentially serious problem.
3. Interpret your confidence interval from 2
Answer:
1. 564 tractor trailers
2. (0.2919, 0.4339)
3. It should be noted that there is 90% confidence that the true population proportion lies between 0.2919 and 0.4339.
Step-by-step explanation:
1)
Proportion= P = 0.8333333333333 (1/12)
Margin error= 0.06/2 = 0.03
Confidence level= 99
Significance level = α= (100 - 99)%= 1%= 0.01
α/2 = 0.01/2 = 0.0005
Sample size= n
= p(1 - p) (Z*/E)
=0.8333333333333 x (2.576/0.03)^2
=563.15
Approximately
=564
2) Sample size n= 124
Sample number of event x =45
Sample proportion = p= x/n
=45/124
= 0.3629
Standard error =√p(1 - p) /n
√(0.3629× (1 - 0.3629)/ 124
= 0.0432
Confidence level= 90
Significance level α= (100-90)% =0.01
Critical value Z* = 1.645
Margin of error = Z×Standard error= 1.645 × 0.0432= 0.07103
Lower limit = p- margin error= 0.3629 - 0.07103= 0.2919
Upper limit = p+margin error= 0.3629 + 0.07103= 0.4339
The answer is (0.2919, 0.4339)
3) It should be noted that there is 90% confidence that the true population proportion lies between 0.2919 and 0.4339.
Factor the expression completely 8x^2-18 Please help
Answer:
2 (2x - 3) x (2x + 3)
Anyone know how to do this?
Step-by-step explanation:
[tex] {5}^{17} \times {5}^{2} [/tex]
Now adding powers
[tex] {5}^{17 + 2} [/tex]
[tex] {5}^{19} [/tex]
Hope it will help :)
Answer:
5x1^19
Step-by-step explanation:
Basically, the only way to have the 5 be to the power of 1 in this equation is to put it in scientific notation, or in other words, multiply 5 by 1 to the power of 19.
HELP!!!! WILL GIVE BRAINLIEST TO FIRST RIGHT ANSWER!!!
A corporation must appoint a president, chief executive officer (CEO), chief operating officer (COO), and chief financial officer (CFO). It must also appoint a planning committee with five different members. There are 14 qualified candidates, and officers can also serve on the committee.
How many different ways can the officers be appointed?
How many different ways can the committee be appointed?
Answer:
A. 24024
B. 364
Step-by-step explanation:
(a) There are 14*13*12*11 = 24024 ways to select the officers...
(b) Since the officers can also serve on the committee, the sampling
is with replacement, so then there are (14 choose 3) ways to
select the committee members... 364 ways to be exact
In the first semester, Jonas took seven tests in his math class. His scores were: 88 81 94 84 100 94 96.
What is the Median of his scores?
A manufacturer produces piston rings for an automobile engine. It is known that ring diameter is normally distributed with millimeters. A random sample of 15 rings has a mean diameter of . Construct a 99% two-sided confidence interval on the true mean piston diameter and a 95% lower confidence bound on the true mean piston diameter. Round your answers to 3 decimal places. (a) Calculate the 99% two-sided confidence interval on the true mean piston diameter.
Complete Question:
A manufacturer produces piston rings for an automobile engine. It is known that ring diameter is normally distributed with ? = 0.001 millimeters. A random sample of 15 rings has a mean diameter of \bar{X}= 74.106. Construct a 99% two-sided confidence interval on the true mean piston diameter and a 95% lower confidence bound on the true mean piston diameter.
(Round your answers to 3 decimal places.)
(Calculate the 99% two-sided confidence interval on the true mean piston diameter.
Answer:
99% true sided confidence Interval on the true mean Piston diameter = (74.105, 74.107)
Step-by-step explanation:
Check the attached file for the complete solution
3
4
of a number is 21. What is the number?
Answer:
28
Step-by-step explanation:
3/4x= 21
x= 21(4/3)
x= 28
Check! (optional)
28 x 3/4 = 21
Check correct!!!!!!
Answer:
the number is 28
Step-by-step explanation:
I know this because 21 is 3/4 of a number. 21 divided by 3 is 7, you do this to find what 1/4 of the number is. so then you add 7 to 22 and you get 28!