Directions: Answer each question below in its entirety. Submit your answers through Canvas by the

due date. Your submission should be a Word document and named with the following structure:

LASTNAME_hw4.doc. Be sure to show your work and to list the names of any students with whom

you worked on this assignment. Please round to the nearest hundredth in your calculations.

Part I: Two-Sample Hypothesis Tests

1.) An Amazon warehouse manager wants to know if their day crew is more time efficient with

their work than the night crew. They draw a random sample of 23 day crew workers and 24

night crew workers. Using these samples, they find that the day crew manages to box an

average of 132 boxes per hour while the night crew manages 122 boxes per hour. The

standard deviation for the day crew is 20 boxes per hour; the standard deviation for the night

crew is 16 boxes per hour. Using this information and an a = .05, decide on the appropriate

hypothesis test, calculate the test statistic, and interpret the results. Be sure to follow the

“five step” system for hypothesis testing outlined in class and in the textbook. Show all of

your work.

2.) An English professor teaching a university-required expository writing class is curious if the

English majors in their class are more likely to read the material prior to lecture than the

non-English majors. The class is much too large to get information from every student, so

they randomly sample 55 English majors and 56 non-English majors in the class. In these

samples, 37% of the English majors and 22% of the non-English majors read the material

prior to class. Using this information and an a = .01, decide on the appropriate hypothesis

test, calculate the test statistic, and interpret the results. Be sure to follow the “five step”

system for hypothesis testing outlined in class and in the textbook. Show all of your work.

3.) A researcher studying perceptions of neighborhood safety wants to know if there is a

difference between men and women when it comes to fear of walking in their neighborhood

at night. They run a hypothesis test in R using the “fear” measure in the 2014 General Social

Survey (GSS)—a dichotomous variable where 0 indicates they are not afraid to walk in their

neighborhood at night and 1 indicates they are afraid. Using the output below, answer the

following questions:

a. What is the dependent variable? What is the independent variable?

b. What test do you think they ran, and why did they run it?

c. What is the null hypothesis? What is the alternative hypothesis?

d. The z-statistic is XXXXXXXXXXWhat is this number telling us? Be sure to interpret it in

relation to the null hypothesis.

e. How would you interpret the outcome of this test? What is the p-value telling you?

SOC 353 2

PAfraid

z -statistic

p-value (twotailed)

Male 0.224

Female 0.421

Difference XXXXXXXXXX

4.) A researcher wants to know if people who see themselves as working class tend to work

longer hours than people who see themselves as middle class. The dependent variable (from

the same GSS dataset as before) is the average number of hours usually worked per week by

the respondent. The researcher runs an independent samples t-test and presents you with the

output below. They interpret the p-value for the one-tailed test to the right as telling them

that there is a 33.85% that the class difference in hours worked is non-zero in the

population. They are happy with these chances, so they say that this difference is statistically

significant. Explain to them why they are wrong, and how they are interpreting the p-value

incorrectly. After you do this, show them how to correctly interpret the results from the test.

n

Mean

t -statistic

p-value (onetailed,

to right)

Working Class XXXXXXXXXX

Middle Class XXXXXXXXXX

Difference XXXXXXXXXX

Part II: Two-Sample Hypothesis Tests in R

5.) There is a dataset called the “Swiss Fertility and Socioeconomic Indicators XXXXXXXXXXData”

(Mosteller and Tukey XXXXXXXXXXThe dataset provides a set of fertility and socioeconomic

variables for 47 French-speaking Swiss provinces around 1888. I have provided an adapted

version of the dataset as part of this assignment. Download the “swiss_data.rds” file and

move it to your working directory. Once it is there, continue with the prompt below.

You are an historical sociologist interested in the following question: “Were provinces with

higher proportions of Catholic residents more likely to have higher proportions of residents

in agricultural occupations than provinces with higher proportions of Protestant residents?”

Looking at the data, you see two relevant variables. The first variable, “Agriculture,” lists the

total proportion of working men in each province with an agricultural profession. The

second variable, “Religion,” is a dichotomous variable where “More Catholic” is a province

where at least 50% of residents are Catholic and “More Protestant” is a province where at

least 50% of residents are Protestant.

Carry out an independent samples t-test in R to answer this question. You will want to carry

out the following commands (once the RDS file is in your working directory):

swiss

t.test(A ~ B, alternative = “C”, var.equal = FALSE)

where the A indicates where you’ll need to specify the dataset (or “object,” in R lingo) and

the dependent variable name, B indicates where need to again specify the dataset and the

SOC 353 3

independent variable name, and “C” indicates whether the test is two-tailed or one-tailed. If

the test is two-tailed, then “C” will be “two.sided”; if the test is one-tailed, then “C” will be

one of “less” or “greater” (depending on the direction of the hypothesis).

Copy and paste the R output showing the t-test into your write-up. After you do that, please

interpret the output. Why did you run an independent samples t-test instead of an

independent samples z-test?

Reference

Mosteller, F. and J. W. Tukey XXXXXXXXXXData Analysis and Regression: A Second Course in Statistics.

Reading, MA: Addison-Wesley.

due date. Your submission should be a Word document and named with the following structure:

LASTNAME_hw4.doc. Be sure to show your work and to list the names of any students with whom

you worked on this assignment. Please round to the nearest hundredth in your calculations.

Part I: Two-Sample Hypothesis Tests

1.) An Amazon warehouse manager wants to know if their day crew is more time efficient with

their work than the night crew. They draw a random sample of 23 day crew workers and 24

night crew workers. Using these samples, they find that the day crew manages to box an

average of 132 boxes per hour while the night crew manages 122 boxes per hour. The

standard deviation for the day crew is 20 boxes per hour; the standard deviation for the night

crew is 16 boxes per hour. Using this information and an a = .05, decide on the appropriate

hypothesis test, calculate the test statistic, and interpret the results. Be sure to follow the

“five step” system for hypothesis testing outlined in class and in the textbook. Show all of

your work.

2.) An English professor teaching a university-required expository writing class is curious if the

English majors in their class are more likely to read the material prior to lecture than the

non-English majors. The class is much too large to get information from every student, so

they randomly sample 55 English majors and 56 non-English majors in the class. In these

samples, 37% of the English majors and 22% of the non-English majors read the material

prior to class. Using this information and an a = .01, decide on the appropriate hypothesis

test, calculate the test statistic, and interpret the results. Be sure to follow the “five step”

system for hypothesis testing outlined in class and in the textbook. Show all of your work.

3.) A researcher studying perceptions of neighborhood safety wants to know if there is a

difference between men and women when it comes to fear of walking in their neighborhood

at night. They run a hypothesis test in R using the “fear” measure in the 2014 General Social

Survey (GSS)—a dichotomous variable where 0 indicates they are not afraid to walk in their

neighborhood at night and 1 indicates they are afraid. Using the output below, answer the

following questions:

a. What is the dependent variable? What is the independent variable?

b. What test do you think they ran, and why did they run it?

c. What is the null hypothesis? What is the alternative hypothesis?

d. The z-statistic is XXXXXXXXXXWhat is this number telling us? Be sure to interpret it in

relation to the null hypothesis.

e. How would you interpret the outcome of this test? What is the p-value telling you?

SOC 353 2

PAfraid

z -statistic

p-value (twotailed)

Male 0.224

Female 0.421

Difference XXXXXXXXXX

4.) A researcher wants to know if people who see themselves as working class tend to work

longer hours than people who see themselves as middle class. The dependent variable (from

the same GSS dataset as before) is the average number of hours usually worked per week by

the respondent. The researcher runs an independent samples t-test and presents you with the

output below. They interpret the p-value for the one-tailed test to the right as telling them

that there is a 33.85% that the class difference in hours worked is non-zero in the

population. They are happy with these chances, so they say that this difference is statistically

significant. Explain to them why they are wrong, and how they are interpreting the p-value

incorrectly. After you do this, show them how to correctly interpret the results from the test.

n

Mean

t -statistic

p-value (onetailed,

to right)

Working Class XXXXXXXXXX

Middle Class XXXXXXXXXX

Difference XXXXXXXXXX

Part II: Two-Sample Hypothesis Tests in R

5.) There is a dataset called the “Swiss Fertility and Socioeconomic Indicators XXXXXXXXXXData”

(Mosteller and Tukey XXXXXXXXXXThe dataset provides a set of fertility and socioeconomic

variables for 47 French-speaking Swiss provinces around 1888. I have provided an adapted

version of the dataset as part of this assignment. Download the “swiss_data.rds” file and

move it to your working directory. Once it is there, continue with the prompt below.

You are an historical sociologist interested in the following question: “Were provinces with

higher proportions of Catholic residents more likely to have higher proportions of residents

in agricultural occupations than provinces with higher proportions of Protestant residents?”

Looking at the data, you see two relevant variables. The first variable, “Agriculture,” lists the

total proportion of working men in each province with an agricultural profession. The

second variable, “Religion,” is a dichotomous variable where “More Catholic” is a province

where at least 50% of residents are Catholic and “More Protestant” is a province where at

least 50% of residents are Protestant.

Carry out an independent samples t-test in R to answer this question. You will want to carry

out the following commands (once the RDS file is in your working directory):

swiss

t.test(A ~ B, alternative = “C”, var.equal = FALSE)

where the A indicates where you’ll need to specify the dataset (or “object,” in R lingo) and

the dependent variable name, B indicates where need to again specify the dataset and the

SOC 353 3

independent variable name, and “C” indicates whether the test is two-tailed or one-tailed. If

the test is two-tailed, then “C” will be “two.sided”; if the test is one-tailed, then “C” will be

one of “less” or “greater” (depending on the direction of the hypothesis).

Copy and paste the R output showing the t-test into your write-up. After you do that, please

interpret the output. Why did you run an independent samples t-test instead of an

independent samples z-test?

Reference

Mosteller, F. and J. W. Tukey XXXXXXXXXXData Analysis and Regression: A Second Course in Statistics.

Reading, MA: Addison-Wesley.

Answered Same DayOct 31, 2021

1)

Step 1:

Ho: there is no significant difference in the mean time-efficiency between day crew and night crew.

h1: day crew is more time efficient with their work than the night crew.

step 2:

alpha = 5%

step 3:

SAMPLE 1

SAMPLE 2

n=

23

24

mean=

132.00

122.00

s=

20.0000

16.0000

s^2/n

17.3913

10.6667

test statistic, t = (Xbar1 - Xbar2) / sqrt(s1^2/n1 + s2^2/n2)

t = = (132 - 122) / sqrt(17.3913+10.6667)

t = 1.8879

Step 4:

df= (s1^2/n1 + s2^2/n2)^2 / ((s1^2/n1)^2/(n1-1) + (s2^2/n2)^2/(n2-1))

df= (17.3913+10.6667)^2 / ( 17.3913^2/(23-1) + 10.6667^2/(24-1) )

df= 42

t(a, df) = t(0.05,42)

t(a, df) = abs(t.INV(0.05,42))

t(a, df) = 1.682

Step 5:

Since t > t(a, df), I reject the null hypothesis at 5% level of significance and conclude that day crew is more time efficient with their work than the night crew.

2)

Step 1:

ho: there is no difference in the proportion of material read prior to lecture for English and non-English majors

h1: English majors in their class are more likely to read the material prior to lecture than the non-English majors

Step 2:

alpha = 1%

Step 3:

p = (p1 * n1 + p2 * n2) / (n1 + n2)

p = (0.37*55+0.22*56)/(55+56)

p = 0.29430

z = (p1 - p2) / sqrt{ p*(1-p) * [ (1/n1) + (1/n2) ]...

Step 1:

Ho: there is no significant difference in the mean time-efficiency between day crew and night crew.

h1: day crew is more time efficient with their work than the night crew.

step 2:

alpha = 5%

step 3:

SAMPLE 1

SAMPLE 2

n=

23

24

mean=

132.00

122.00

s=

20.0000

16.0000

s^2/n

17.3913

10.6667

test statistic, t = (Xbar1 - Xbar2) / sqrt(s1^2/n1 + s2^2/n2)

t = = (132 - 122) / sqrt(17.3913+10.6667)

t = 1.8879

Step 4:

df= (s1^2/n1 + s2^2/n2)^2 / ((s1^2/n1)^2/(n1-1) + (s2^2/n2)^2/(n2-1))

df= (17.3913+10.6667)^2 / ( 17.3913^2/(23-1) + 10.6667^2/(24-1) )

df= 42

t(a, df) = t(0.05,42)

t(a, df) = abs(t.INV(0.05,42))

t(a, df) = 1.682

Step 5:

Since t > t(a, df), I reject the null hypothesis at 5% level of significance and conclude that day crew is more time efficient with their work than the night crew.

2)

Step 1:

ho: there is no difference in the proportion of material read prior to lecture for English and non-English majors

h1: English majors in their class are more likely to read the material prior to lecture than the non-English majors

Step 2:

alpha = 1%

Step 3:

p = (p1 * n1 + p2 * n2) / (n1 + n2)

p = (0.37*55+0.22*56)/(55+56)

p = 0.29430

z = (p1 - p2) / sqrt{ p*(1-p) * [ (1/n1) + (1/n2) ]...

SOLUTION.PDF## Answer To This Question Is Available To Download

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