Questions
Use data from Excel to complete problems 3.1 and 3.2. When you open the file look...

Use data from Excel to complete problems 3.1 and 3.2. When you open the file look at the tabs on the bottom left. You will use the data from the “Class_LabScores” tab to answer these questions.

Frequency distribution tables for Dr. Wallace's three statistics courses
X = quiz scores
Class 1 Class 2    Class 3
X f X f X f
0 3 0 0 0 3
1 0 1 0 1 0
2 0 2 0 2 1
3 2 3 3 3 0
4 3 4 2 4 0
5 6 5 1 5 2
6 4 6 2 6 3
7 2 7 0 7 1
8 3 8 4 8 1
9 2 9 2 9 0
10 1 10 3 10 0
11 4 11 4 11 2
12 3 12 3 12 4
13 8 13 6 13 6

3.1. Dr. Wallace teaches three statistics labs at three different times of day (1 - morning, 2 - noon, 3 - night). She is curious to find out whether or not time of day is related to student scores on the lab assignments. Frequency distribution tables for each of her three lab classes appear on the “Class_LabScores” tab in the Excel file. Please calculate the following:

Mean for Morning Class 1:

Mean for Noon Class 2:

Mean for Night Class 3:

3.2 Dr. Wallace is preparing a summary of her teaching experience in the statistics lab classes. She only wants to use one number to represent student performance in those classes, so she’ll need to calculate one mean. In addition, she wants to be fair and make sure that every student’s lab score contributes equally to the overall mean. In order to do this, she needs to calculate the weighted mean. Please calculate the following and show work:

Weighted mean for her statistics classes:

In: Math

The objective of the question is to test the Hypothesis If the Mean travel time in...

The objective of the question is to test the Hypothesis If the Mean travel time in minutes between Point A to Point B is equal to the mean of the travel time in minutes from Point B to your A. First you must find the mean and standard deviations. Then perform and list the complete required steps for the TWO required Hypothesis tests and use the P-Value as a rejection Rule for both tests.

One Hypothesis test is an F test for the equality of the variances of travel Times and the second test is a T test for the equality of the means of travel times in minutes. The F test must be performed first in order to select either Case1 or Case 2 for the T-test.

Recorded Time values in minutes from point A to point B in minutes: 32, 34, 51, 30, 29, 35, 36, 29, 32, 29, 33, 32, 29, 30, 33, 30, 30, 33, 30, 31, 35, 35, 34, 33, 31, 34, 30, 30, 29, 34, 32, 35, 29, 30, 32, 30, 33, 31

nA=38

Recorded Time values in minutes from point B to point A in minutes: 36, 28, 48, 28, 27, 54, 34, 29, 26, 34, 33, 42, 29, 34, 31, 4, 27, 42, 28, 45, 26, 43, 32, 30, 27, 29, 29, 35, 26, 31, 28, 27, 28, 32, 41, 34, 28, 31

nB=38

In: Math

Describe some of the benefits of using a survey design in quantitative research.

Describe some of the benefits of using a survey design in quantitative research.

In: Math

Background: This activity is based on the results of a recent study on the safety of...

Background: This activity is based on the results of a recent study on the safety of airplane drinking water that was conducted by the U.S. Environmental Protection Agency (EPA). A study found that out of a random sample of 316 airplanes tested, 40 had coliform bacteria in the drinking water drawn from restrooms and kitchens. As a benchmark comparison, in 2003 the EPA found that about 3.5% of the U.S. population have coliform bacteria-infected drinking water. The question of interest is whether, based on the results of this study, we can conclude that drinking water on airplanes is more contaminated than drinking water in general.

Question 1: (Remember write all answer in an MS Word doc and upload)

Let p be the proportion of contaminated drinking water in airplanes. Write down the appropriate null and alternative hypotheses.

Question 2:

Based on the collected data, is it safe to use the z-test for p in this scenario? Explain.

Use the following instructions to conduct the z-test for the population proportion:

Instructions - 2 Options

Option 1: Click on the following link to use the MS Excel hypothesis test template: hypothesis.xls
R | StatCrunch | Minitab | Excel 2007 | TI Calculator

Question 3:

Now that we have established that it is safe to use the Z-test for p for our problem, go ahead and carry out the test. Paste the output below.

Question 4:

What is the test statistic for this test? (Hint: Calculation already done by either technology option.) Interpret this value.

Question 5:

What is the P-Value? Interpret what that means, and draw your conclusions. Assume significance level of 0.05.

In: Math

An animal’s maintenance caloric intake is defined as the number of calories per day required to...

An animal’s maintenance caloric intake is defined as the number of calories per day required to maintain its weight at a constant value. We wish to discover whether the median maintenance caloric intake, m, for a population of rats is less than 10g/day. We draw a SRS of 17 rats, feed each rat 10g of dry food per day for30 days, and find that 4 of the rats lost weight, while the rest gained weight.

(a) State null and alternative hypotheses in terms of m.

(b) Let B be the number of rats in a SRS of size 17 that exhibit daily caloric demands more than 10g/day.IfH0is true, what is the distribution ofB?

(c) What is the value of B observed in the study?

(d) Use the sign test to calculate the p-value and draw a conclusion using α= 0.05.

In: Math

In a time-use study, 20 randomly selected college students were found to spend a mean of...

In a time-use study, 20 randomly selected college students were found to spend a mean of 1.4 hours on the internet each day. The standard deviation of the 20 scores was 1.3 hours.
Construct a 90% confidence interval for the mean time spent on the internet by college students. Assume t* = 1.729
If you increased the sample size for the problem above, what would happen to your confidence interval, assuming the sample mean and standard deviation remain unchanged?

In: Math

A study is conducted regarding shatterproof glass used in automobiles. Twenty-six glass panes are coated with...

A study is conducted regarding shatterproof glass used in automobiles. Twenty-six glass panes are coated with an anti-shattering film. Then a 5-pound metal ball is fired at 70mph at each pane. Five of the panes shatter. We wish to determine whether, in the population of all such panes, the probability the glass shatters under these conditions is different from π= 0.2

(a) State the appropriate null and alternative hypotheses.

(b) Check the conditions for trusting the conclusion of the test, and calculate the observed value of an appropriate test statistic.

(c) Calculate the rejection region and draw a conclusion, given the significance level α= 0.05.

(d) Calculate the p-value.

(e) Compute the power of the test if the trueπwas in fact 0.3.

In: Math

W72A) I am learning EXCEL Functions. Please answer in EXCEL Functions in detail Stock Returns (relationship...

W72A) I am learning EXCEL Functions. Please answer in EXCEL Functions in detail

Stock Returns (relationship between hypothesis testing and confidence intervals)

Suppose you as an investor with a stock portfolio of hundreds of thousands of dollars decide to sue your broker because of low returns due to lack of portfolio diversification, i.e., too many holdings with similar return prospects. The 39 monthly returns, expressed as percentages, are shown in the table below and reproduced in your Excel answer template.

-8.36

1.63

-2.27

-2.93

-2.70

-2.93

-9.14

-2.64

6.82

-2.35

-3.58

6.13

7.0

-15.25

-8.66

-1.03

-9.16

-1.25

-1.22

-10.27

-5.11

-0.80

-1.44

1.28

-0.65

4.34

12.22

-7.21

-.09

7.34

5.04

-7.24

-2.14

-1.01

-1.41

12.03

-2.56

4.33

2.35

If we graph these data in a histogram, we can reasonably infer that the data are distributed normally.

Suppose you’re on an arbitration panel reviewing this case and decide to compare these returns with the Standard & Poor’s (S&P’s) stock index over the same period and find that the S&P mean, which we can interpret as the population mean (μ), equals .95%.

  1.        Test (two-sided) at the 5% level that the mean return you compute   from the investor’s 39-month sample differs from the S&P (population) mean. Use the P-value method, rounding to 4 digits. Make sure to state the null and alternate hypotheses, claim, and your conclusion.   

Remember: since we must compute the sample standard deviation, use the t-statistic to perform the test.)

  1.       Now use your P-value calculated in (a) to test at the 1% level whether the sample mean differs from the S&P population main, making sure to state your conclusion. (Do not restate the hypotheses. Simply state the conclusion.

  1.        Compute a 95% confidence interval for the population mean,

using the data given in the Table above for α = .05. (Express the results with three decimal places, one more than given in the data.) Does the S&P mean lie in the interval you’ve computed?

  1.        Now compute a 99% confidence interval for the population mean, expressing the results with three decimal places. Does the S&P mean lie in the interval you’ve computed?

In: Math

The mean pay in 2008 Bh CEOsat the 500 biggest U.S. companies was 12.8 million dollars.””...

The mean pay in 2008 Bh CEOsat the 500 biggest U.S. companies was 12.8 million dollars.”” Public outcry and stockholder complaints have forced compensation committees to reconsider senior executive salaries. A random sample of CEOs was obtained, and the total pay (in millions of dollars) for each is given in the following table.

10.1 4.3 13.8 5.1 13.0 21.2 4.5 10.5 17.6 10.1 6.5 9.9 13.3 20.4

Is there any evidence to suggest that the mean pay for CEOs has decreased? Use a = 0.05 and assume normality.

In: Math

Problem 1 ✓ Problem 2 Problem 3 ✓ Problem 4 … Problem 5 … Problem 6...

  • Problem 1 ✓
  • Problem 2
  • Problem 3 ✓
  • Problem 4 …
  • Problem 5 …
  • Problem 6 ✓
  • Problem 7
  • Problem 8
  • Problem 9

close sidebar

  • webwork
  • /
  • f2019stat213
  • /
  • stat_213_assignment_3
  • /
  • 5

STAT 213 Assignment 3: Problem 5

Previous Problem Problem List Next Problem

(1 point)

To examine the effectiveness of its four annual advertising promotions, a mail order company has sent a questionnaire to each of its customers, asking how many of the previous year's promotions prompted orders that would not have otherwise been made. The accompanying table lists the probabilities that were derived from the questionnaire, where X is the random variable representing the number of promotions that prompted orders. If we assume that overall customer behavior next year will be the same as last year, what is the expected number of promotions that each customer will take advantage of next year by ordering goods that otherwise would not be purchased?

X 0 1 2 3 4
P(X) 0.072 0.221 0.347 0.176 0.184

Expected value =

equation editor

Equation Editor

A previous analysis of historical records found that the mean value of orders for promotional goods is 35 dollars, with the company earning a gross profit of 22% on each order. Calculate the expected value of the profit contribution next year.

Expected value =

equation editor

Equation Editor

The fixed cost of conducting the four promotions is estimated to be 17000 dollars with a variable cost of 2 dollars per customer for mailing and handling costs. What is the minimum number of customers required by the company in order to cover the cost of promotions? (Round your answer to the next highest integer.)

Breakeven point =

equation editor

Equation Editor

In: Math

1. The table below contains price-demand and total cost data for the production of projectors, where...

1. The table below contains price-demand and total cost data for the production of projectors, where p is the wholesale price (in dollars) of a projector for an annual demand of x projectors and C is the total cost (in dollars) of producing x projectors.

x1 p c
1943 1035 900
3190 581 1130
4570 405 1241
6490 124 1800
7330 85 1620

Price-Demand:

a. Make a scatter plot for p vs x (price-demand plot).

b. Get a regression line that best fits the data in Question a. You need to type the equation of this line in desmos and graph it with your scatter plot. Please use p(?1) = equation when typing in desmos.

c. Does it look like the regression line models the data well? (Yes or No) Why?

d. Use the equation typed in desmos to find p(0), p(3000), p(6000) 5. What value of x would make p(x) = 0?

In: Math

1.Crop rotation is a common strategy used to improve the yields of certain crops in subsequent...

1.Crop rotation is a common strategy used to improve the yields of certain crops in subsequent growing seasons. An experiment was performed to assess the effects of crop rotation plant type and crop rotation plant density levels on the yield of corn, the primary crop of interest. A field was separated into 12 plots and each of the treatments was randomly applied. After 2 months of growth of the rotated crops, the plots were cleared, and corn seeds were applied evenly to each plot. After 5 months of growth of the corn, the yields were assessed. The data, in kg/m2, are shown below. Determine if crop rotation plant type and density affect the yields of corn in this field. What treatment should the farmers use to maximize the yield?

Density (k/ha)

Rotation Variety

05 k/ha

10 k/ha

15 k/ha

20 k/ha

Pea

7.8

11.2

18.5

15.4

9.1

12.7

16.7

14.7

10.6

13.3

15.4

11.3

Soy

7

9.3

13.8

11.3

6.7

10.9

14.3

12.7

8.1

11.8

15.4

14.3

Wheat

6.4

4.9

3.6

2.8

4.5

7.1

3.9

6.1

5.9

3.2

5.8

4.6

  1. What kind of statistical test will you be performing?
  2. Will you need to test for equal variance? If so what are your results and how does that influence the next steps in your analysis?
  3. What are your null and alternative hypotheses?
  4. Discuss the results of your analysis. Will you accept or reject your null hypothesis? Why? What can you specifically say about the data?

In: Math

For each of the different confidence levels given below determine the appropriate z* to use to...

For each of the different confidence levels given below determine the appropriate z* to use to create a confidence interval for the population proportion. (Give the positive z* value, rather than the negative.)

C= 88%, z*=

C= 93%, z*=

C= 72%, z*=

In: Math

The heat evolved in calories per gram of a cement mixture is approximately normally distributed. The...

The heat evolved in calories per gram of a cement mixture is approximately normally distributed. The population mean is thought to be 100, and the population standard deviation σ is 2. You wish to test H0 : µ = 100 versus H1 : µ 6= 100. Note that this is a two-sided test and they give you σ, the population standard deviation. (a) State the distribution of X¯ assuming that the null is true and n = 9.

(b) Find the boundary of the rejection region for the test statistic (these critical values will be z-values) if the type I error probability is α = 0.01.

(c) Find the boundary of the rejection region in terms of ¯x if the type I error probability is α = 0.01. In other words, how much lower than 100 must X¯ be to reject and how much higher than 100 must X¯ be to reject. You will have an ¯xlow and an ¯xhigh defining the rejection region. HINT: You are un-standardizing your z from part (b) here.

(d) What is the type I error probability α for the test if the acceptance region for the hypothesis test is instead defined as 98.5 ≤ x¯ ≤ 101.5? Recall that α is the probability of rejecting H0 when H0 is actually true.

In: Math

​​​​​​The following table shows age distribution and location of a random sample of 166 buffalo in...

​​​​​​The following table shows age distribution and location of a random sample of 166 buffalo in a national park.

Age Lamar District Nez Perce District Firehole District Row Total
Calf 14 14 13 41
Yearling 12 9 12 33
Adult 30 28 34 92
Column Total 56 51 59 166

Use a chi-square test to determine if age distribution and location are independent at the 0.05 level of significance.

(a) What is the level of significance?


State the null and alternate hypotheses.

H0: Age distribution and location are not independent.
H1: Age distribution and location are not independent.H0: Age distribution and location are independent.
H1: Age distribution and location are independent.    H0: Age distribution and location are not independent.
H1: Age distribution and location are independent.H0: Age distribution and location are independent.
H1: Age distribution and location are not independent.


(b) Find the value of the chi-square statistic for the sample. (Round the expected frequencies to at least three decimal places. Round the test statistic to three decimal places.)


Are all the expected frequencies greater than 5?

YesNo    


What sampling distribution will you use?

uniformchi-square    normalStudent's tbinomial


What are the degrees of freedom?


(c) Find or estimate the P-value of the sample test statistic. (Round your answer to three decimal places.)

p-value > 0.1000.050 < p-value < 0.100    0.025 < p-value < 0.0500.010 < p-value < 0.0250.005 < p-value < 0.010p-value < 0.005



(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis of independence?

Since the P-value > α, we fail to reject the null hypothesis.Since the P-value > α, we reject the null hypothesis.    Since the P-value ≤ α, we reject the null hypothesis.Since the P-value ≤ α, we fail to reject the null hypothesis.


(e) Interpret your conclusion in the context of the application.

At the 5% level of significance, there is sufficient evidence to conclude that age distribution and location are not independent.At the 5% level of significance, there is insufficient evidence to conclude that age distribution and location are not independent.    

In: Math