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Statistics, section 2, Fall 2019
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Mendenhall et al-Intro Prob & Stats (Metric) 15e (Homework)

James Finch

Statistics, section 2, Fall 2019

Instructor: Dr. Friendly

Current Score : 15 / 65

Due : Sunday, January 27, 2030 23:30 EST

Last Saved : n/a Saving... ()

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Question

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3/5	3/6	0/2	1/5	0/4	3/4	–/9	–/18	1/3	4/9

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15/65 (23.1%)

Instructions

Introduction to Probability and Statistics (Metric Version), 15th edition, by Mendenhall, Beaver, and Beaver, published by Cengage Learning, is a major overhaul from the previous edition, lowering the reading level, introducing concepts in a more intuitive way and significantly increasing homework scaffolding for difficulty level. Written in compliance with the GAISE college report, this text teaches students to become problem solvers who are adept at using technology to facilitate statistical reasoning as well as the interpretation of statistical results. Students will be able to describe real sets of data meaningfully, what the statistical tests mean in terms of their practical applications, how to evaluate the validity of the assumptions behind statistical tests and know what to do when statistical assumptions have been violated. The 15th edition contains 1884 exercises, employs real data throughout, and includes at least 75% new or updated examples. Introduction to Probability and Statistics (Metric Version), 15th edition, adds new sections on the uniform and exponential distributions, normal probability plots for assessing normality, best subsets regression procedures and binary logistic regression. The WebAssign component for this text engages students with an interactive eBook and several other resources.

These questions show a variety of question types available in WebAssign for use with this title.

Question 1 asks students to answer multiple choice questions about pie charts.

Question 2 asks students to think through a linear regression scenario then numerically enter statistics and a regression equation.

Question 3 asks students to answer multiple select questions about side-by-side boxplots.

Question 4 walks students through the steps for a hypothesis test.

Question 5 is a Simulation Question utilizing the JMP Applet.

Question 6 is a Stats in Practice question that demonstrates the use of videos displayed within a question, followed by multiple choice and discussion questions in a unique two-part accordion style of display.

Question 7 is an example of a Statistical Lab. These activities support SPSS, Minitab, R, JMP, Excel, and TI 83/84 or TI-Inspire calculators.

Question 8 highlights Milestone 1, the first step in presenting and tracking Project milestones for a statistical research project.

Question 9 is a Concept Question where students are asked to provide a short answer to a prompt, then answer a multiple choice question about the same prompt, then reflect on their original answer.

Question 10 provides assistance to students as they work through the steps for a hypothesis test. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

The answer key and solutions will display after the first submission for demonstration purposes. Instructors can configure these to display after the due date or after a specified number of submissions.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. 3/5 points | Previous Answers MendStat15M 3.1.012. My Notes

When you were growing up, did you feel that you did not have enough free time? Parents and children have differing opinions on this subject. A research group surveyed 198 parents and 200 children and recorded their responses to the question, "How much free time does your child have?" or "How much free time do you have?" The responses are shown in the table below.

	Just the Right Amount	Not Enough	Too Much	Don't Know
Parents	138	14	40	6
Children	130	48	16	6

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2. 3/6 points | Previous Answers MendStat15M 3.2.025. My Notes

Male crickets chirp by rubbing their front wings together. They chirp faster with increasing temperatures and slower with decreasing temperatures. The following table shows the number of chirps per second for a cricket, recorded at 10 different temperatures.

Chirps per second	24	20	23	22	22	20	18	21	19	20
Temperature	31	23	33	29	28	24	21	28	21	28

(a)

Which of the two variables (temperature and number of chirps) is the independent variable, x?

temperature number of chirps

Which of the two variables (temperature and number of chirps) is the dependent variable, y?

temperature correct

number of chirps

(b)

Plot the data using a scatterplot.

A scatterplot has 10 points.

The horizontal axis is labeled: "x", and ranges from 20 to 34.

The vertical axis is labeled: "y", and ranges from 17 to 25.

Moving from left to right, the points are plotted in an upward, diagonal direction starting in the lower left corner of the diagram.

The points are between 21 and 33 on the horizontal axis and 18 and 24 on the vertical axis.

A scatterplot has 10 points.

The horizontal axis is labeled: "x", and ranges from 17 to 25.

The vertical axis is labeled: "y", and ranges from 20 to 34.

Moving from left to right, the points are plotted in an upward, diagonal direction starting in the lower left corner of the diagram.

The points are between 18 and 24 on the horizontal axis and 21 and 33 on the vertical axis.

How would you describe the relationship between temperature and number of chirps?

Temperature and number of chirps per second show a positive linear relationship. As temperature increases chirps per second tends to be lower. Temperature and number of chirps per second show a negative linear relationship. As temperature increases chirps per second tends to be higher. Temperature and number of chirps per second show a negative linear relationship. As temperature increases chirps per second tends to be lower. Temperature and number of chirps per second show a positive linear relationship. As temperature increases chirps per second tends to be higher.

(c)

Find the least-squares line relating the number of chirps to the temperature. (Round your numeric values to three decimal places.)

y =

√5

$webMathematica generated answer key$

(d)

If a cricket is monitored at a temperature of 30 degrees, what would you predict his number of chirps would be? (Round your answer to the nearest whole number.)

chirps

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3. 0/2 points | Previous Answers MendStat15M 3.R.010. My Notes

4. 1/5 points | Previous Answers MendStat15M 9.2.026. My Notes

A company was contemplating the installation of a flextime schedule in which a worker schedules his or her work hours or compresses work weeks. The company estimates that it needs a minimum mean of 7 hours per day per assembly worker in order to operate effectively. Each of a random sample of 70 of the company's assemblers was asked to submit a tentative flextime schedule. If the mean number of hours per day for Monday was 6.7 hours and the standard deviation was 2.3 hours, do the data provide sufficient evidence to indicate that the mean number of hours worked per day on Mondays, for all of the company's assemblers, will be less than 7 hours? Test using α = 0.05.

State the null and alternative hypotheses.

H₀: μ = 7 versus H_a: μ > 7

H₀: μ ≠ 7 versus H_a: μ = 7

H₀: μ = 7 versus H_a: μ < 7

H₀: μ < 7 versus H_a: μ > 7

H₀: μ = 7 versus H_a: μ ≠ 7

Find the test statistic and rejection region. (Round your answers to two decimal places. If the test is one-tailed, enter NONE for the unused region.)

test statistic	z = -1.09
rejection region	z > NONE
	z < -1.645

State your conclusion.

H₀ is not rejected. There is insufficient evidence to indicate that the mean number of hours will be less than 7. H₀ is not rejected. There is sufficient evidence to indicate that the mean number of hours will be less than 7. H₀ is rejected. There is sufficient evidence to indicate that the mean number of hours will be less than 7. H₀ is rejected. There is insufficient evidence to indicate that the mean number of hours will be less than 7.

You may need to use the appropriate appendix table or technology to answer this question.

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5. 0/4 points | Previous Answers MendStat15M 3.JMP.002. My Notes

6. 3/4 points | Previous Answers MendStat15M 3.SIP.001. My Notes

Stats in Practice: Correlation and Regression

Part I - Multiple Choice Questions

The video discusses a survey conducted by FreeCreditScore.com that found that when choosing a long term partner, respondents ranked financial responsibility as important as what characteristic of the potential partner?

age net worth     physical attractiveness intelligence

What type of variable is a credit score?

categorical qualitative     quantitative

A positive correlation (or relationship) between two variables means that as one increases, the other increases. In contrast, a negative correlation means that as one increases, the other decreases. If a higher credit score indicates a better credit history, then the video implies that the correlation between credit scores of a partner and the number of years the relationship with that partner lasts ("relationship longevity") is which of the following?

positive negative
Part II - Discussion Question

Describe a quantitative variable not mentioned in the video that you would expect to have a positive relationship with a person's credit score. That is, people who tend to have higher credit scores also tend to have higher values of your selected variable. Describe why you are guessing that the relationship between credit score and your chosen variable is positive.

i think the relationship is positively correlated to financial stability

This answer has not been graded yet.

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7. –/9 points MendStat15M 1.Lab.001.Excel. My Notes

Statistical Lab

Background

The National Institutes of Health conducts ongoing surveys of US adults called the Health Information National Trends Survey (hereafter abbreviated HINTS).

From the National Institutes of Health: "The HINTS data collection program was created to monitor changes in the rapidly evolving field of health communication. Survey researchers are using the data to understand how adults 18 years and older use different communication channels, including the Internet, to obtain vital health information for themselves and their loved ones...."

A doctor and a patient are talking in an examination room.

The most recent round of data collection occurred over the course of September 2013–November, 2013 in HINTS 4 Cycle 3. In this lab, you will be using a subset of the HINTS 4 Cycle 3 data to practice creating effective and informative graphical representations of data, which may include histograms and pie charts.
About the Data
For this lab, you need to download the hintsdata.csv dataset. The variables you will be working with are as follows.
- Age—assume each person's age was rounded to the nearest year; for example, a person in the age
  range [19.5, 20.5)
  would have a reported age of 20, and a person in the
  range [20.5, 21.5)
  would have a reported age of 21, and so on.
- Gender—the gender of the respondent; categories include 1 = Male and 2 = Female.
- GeneralHealth—how the respondent rates their overall health; categories include 1 = Excellent, 2 = Very Good, 3 = Good, 4 = Fair, 5 = Poor.
General Notes
A few important aspects of creating effective graphical displays of data include the following.
1. labeling your graphs with descriptive titles
2. ensuring that the x- and y-axes have appropriate labels
3. setting the axes to meaningful and/or useful scales
Your graphs are expected to have these three characteristics.
Tech Guide

You will need to use the Excel Tech Guide.
Lab Questions

Create a histogram of the variable Age with class intervals 10 years wide. (Submit a file with a maximum size of 1 MB.)

hintsdata.csv

This answer has not been graded yet.

Describe the shape of the above histogram.

The distribution is , centered near , with variability.

Create a pie chart of the variable GeneralHealth. (Submit a file with a maximum size of 1 MB.)

hintsdata.csv

This answer has not been graded yet.

Describe how the majority of people in the survey feel about their general state of health.

The majority of people in the survey feel that their general state of health is .

You wish to determine if the age of the respondents who perceive themselves to be in good health differs from the age of the respondents who perceive themselves to be in poor health. Do this by creating two histograms. For the first histogram, plot the variable Age using only the data from respondents who rate their overall health as Excellent, Very Good, or Good. For the second histogram, plot the variable Age using only the data from respondents who rate their overall health as Fair or Poor. Make sure to label your histograms and make sure that they have the same limits for the x-axis, y-axis, and class intervals, so that they can be directly compared. (Submit a file with a maximum size of 1 MB.)

This answer has not been graded yet.

Briefly discuss.

This answer has not been graded yet.

Compare how men and women rate their general state of health using a comparative chart. Using your chart, briefly compare and contrast how men and women rate their general state of health.

This answer has not been graded yet.

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8. –/18 points MendStat15M PJT.1.001. My Notes

Question Part

Points

Submissions Used

–/1

0/100

Total

–/18

Milestone 1: Research Design

Question 1

What is your research question?

Your research question should be based on a topic that interests you and that you can reasonably obtain data for. Try to make your research question as specific as possible. Form a research question about a population that you will be able to sample. Some examples of research questions are: "Are students at my college able to taste the difference between regular coffee and decaffeinated coffee?", "Does the GPA, age, and number of credits needed for graduation for juniors at my university differ between transfer students and non-transfer students?", "Have the new water rates in my water district changed residents' water usage habits?", and "Do recent graduates from the business department at my university get larger starting salaries on average if they have participated in a summer internship?"

This answer has not been graded yet.
Question 2

Has any research already been done that might help with your project?

You can search your university's online database to find articles that discuss research that has already been done on your research question. Please make note of any articles or other sources that helped guide your research question and research design. You will be asked to provide references to any sources you used.

This answer has not been graded yet.
Question 3

What is your population of interest?

Your population of interest will be closely related to your research question. For instance, if you are testing the freshman 15 theory and you believe that students at your college do not gain 15 pounds on average over the course of freshman year, then your population of interest is the students at your college who have completed freshman year.

This answer has not been graded yet.
Question 4

Describe your sampling plan.

You want to ensure that your sample is representative of the population of interest. How will you target your population of interest? Sampling involves tradeoffs; you may have to settle for a convenience sample, which is fine for this project as long as you acknowledge this. Sampling is about doing the best you can with the resources you have at your disposal.

This answer has not been graded yet.
Question 5

Will this sample be representative of the population of interest? If so, why? If not, what population will the sample be representative of?

Is there any group of people within the population of interest that your sampling plan is likely to miss? For instance, if you are using a random sample of landline telephone numbers from your state in order to achieve a random sample of residents in your state, then you are missing all of the residents of your state who only have a cell phone and do not have a landline. Or, if your population of interest is all adults in your country, but you only conduct interview of adults from your local community, then your sample is only representative of the adults in your local community.

This answer has not been graded yet.

Question 6

What variables will you measure?

Make sure that the variables you choose are measurable. If you are performing an experiment where you are comparing two skin creams to determine which gives the skin a more youthful glow, how exactly will you measure "youthful glow"? Are there other variables that you will collect because they too may be of interest? Age? Gender? Level of education? Is your variable type numeric or categorical? If your variable type is numeric, is it discrete or continuous? Do your variables need to be measured using special equipment?

Variable	Type	How will you measure it?
		This answer has not been graded yet.
		This answer has not been graded yet.
		This answer has not been graded yet.
		This answer has not been graded yet.

Question 7

Describe your study design.

Will you be conducting an observational study or performing an experiment? What will your sample size be? If you will be performing an experiment, will there be a placebo? If so, describe the placebo. Will the experiment be blinded? Double-blinded? Who will carry out the experiment and how?

This answer has not been graded yet.

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9. 1/3 points | Previous Answers MendStat15M 6.CQ.005. My Notes

Car insurance rates for teenagers are generally higher than insurance rates for adult drivers.

Part 1 of 3

If car insurance rates for teenagers are approximately normally distributed with a standard deviation of $670 per year, find the mean insurance rate for teenagers if 10.56% of teenagers pay more than $4,000 annually for car insurance. (Use a table or technology. Round your answer to the nearest dollar.)

Key: Answers may vary.

Score: 1 out of 1

Comment:

This question is not automatically graded. Your instructor will review your answer at a later time.

If car insurance rates for teenagers is approximately normally distributed with a standard deviation of $670 per year, find the mean insurance rate for teenagers if 10.56% of teenagers pay more than $4,000 annually for car insurance. (Use a table or technology. Round your answer to the nearest dollar.)

(a) $3,163 (b) $4,838 (c) $3,929 (d) $3,330

Incorrect.
z =

x − μ

Note that σ = $670 and now one must find μ. If 10.56% pay more than $4,000, then $4,000 is on the right side of the normal curve with 10.56% of the normal curve area to the right of it.
Working backwards: given the probability, find the z-value. Since the question involves ">," one needs to subtract probability from 1.0, 1 − 0.1056 = 0.8944, for both the table or technology, as both work with cumulative probabilities.
Table: Go to the inside of the table and get as close as possible to 0.8944, then read the corresponding z-value from the margins. z = 1.25
Then set

1.25 =

4,000 − μ

670

Solving for μ gives $3,163.
(b) Used z = −1.25. That has 10.56% to the left under the normal curve. This corresponds to "less than", but "more than" is needed here.
(c) Change the 10.56% into the form of a z value. Do not use 10.56 in the z formula.
(d) Subtracting 1 standard deviation from $4,000 provides no additional information to help calculate μ.

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10. 4/9 points | Previous Answers MendStat15M 9.2.029. My Notes

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Welcome, demo@demo

Mendenhall et al-Intro Prob & Stats (Metric) 15e (Homework)

Current Score : 15 / 65

Due : Sunday, January 27, 2030 23:30 EST

Last Saved : n/a Saving... ()

Instructions

Assignment Submission

Assignment Scoring

JMP Applet

(a)

(b)

(c)

(d)

Stats in Practice: Correlation and Regression

Part I - Multiple Choice Questions

Part II - Discussion Question

Statistical Lab

Background

About the Data

General Notes

Tech Guide

Lab Questions

Milestone 1: Research Design

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7