Stats

Lab 4 STA 2023

The purpose of this Lab is to allow you to apply some of the statistical tools we learned in the first three chapters to real world data sets.

You may work with others in the course or you may work individually. Each student must submit his or her own document in Canvas. If you work with other students on the assignment, you must acknowledge them on your submission.

We will be using the StatCrunch or Excel file dataset: Janssens Summer 2018 Intro Stats Lab 3.xlsx. You can find this dataset by going to StatCrunch , click on the Explore tab, then in the right hand search box type in “Janssens”. There is also a copy of the Excel spreadsheet containing the data posted with the assignment. (See the Powerpoint “Lab 1 Information” in Module 2 for a refresher on how to find the data and do analysis in StatCrunch )

Step 1: Original Submission 4 possible points

You must answer all of the following questions and must submit an online document in pdf format with the answers.

All questions must be answered in full sentences.

You can use any tool you wish to answer the questions; StatCrunch, Excel, your calculator where appropriate or any online stats tool that you are comfortable with.

Each student must make their own submission to the Canvas Assignment Lab. If you work with other students on the assignment, you must acknowledge them on your submission.

If you do not submit a document with all questions answered by the first due date, you will get no points for this Lab. Labs are worth 30% of your course grade.

Once you have submitted your answers to the original Canvas Assignment, post your answers in pdf format in your Group’s Files right away.

Step 2 Group Learning and Final Submission 1 possible point

You must view the submissions of the other students in your Group and in the Discussions section of your Group and make comments on at least one other student’s submission. Good comments ask questions, share learnings, suggest upgrades, and acknowledge strengths.

You can earn up to 1 point for this assignment by making substantive comments on your group members submissions. “Hey, that looks great” does not count as a substantive comment.

If you submit to your Group close (after 3pm on the due date for final submission) to the deadline then your comments won’t help your Group mates and there is no real chance for substantive dialogue so your submission will not get the point available for this part of the assignment.

You can make changes to your original submission based on comments that you have received and resubmit. Your final score on the assignment will be based on the final submission if you make one or your original submission if you do not. There will be no “late penalty” for resubmitting your assignment. Post your edited resubmission to the original Canvas Assignment.

Question 1

A student organization wants develop a program for students who are going to graduate in the next 18 months. To get a sense of how many students might be interested in the program, they want an estimate of the proportion of students who are going to graduate in the next 18 months. They take a simple random sample of 89 students. The data they collected can be found in the column labeled “Graduate in the next 18 month”. “No” means that the student will not graduate in the next 18 months and would not be of interest to the student organization. “Yes” means that the student will graduate in the next 16 months and would be of interest to the student organization.

a) The vice president of the student organization has asked you to create an estimate of the proportion of students who will graduate in 18 months. You ask her what level of confidence she wants to have in the estimate and she says that she would like to be 90% confident in the proportion estimate. Create the confidence interval using the sample data. Write a sentence or two to communicate the results to her.

Question 2

A student organization wants to get an estimate of the proportion of students who would attend a Tiny Cowboys concert at Al Lang stadium. They ask you how many students they should include in their sample to get this estimate.

a) They tell you that a similar concert held at another college close by had 24% of all students attend the concert, they would be ok with being 90% confident and want the estimate to be within 6% of the true value. Calculate the sample size. Write a sentence or two to communicate to the student organization how many students that they should sample.

Question 3

The Student Government Association is interested in an estimate of the mean hours students work per week. They take a simple random sample of 89 students. The data they collected can be found in the column labeled “Number of hours worked per week”.

a) Use the sample data to construct a 95% confidence interval for the mean number hours worked. Write one or two sentences to communicate to the Student Government the estimate and the margin of error.

Question 4

An administrator said that he believes more than 25% of all students will graduate in the next 18 months.

Use the data found in the column labeled “Graduate in the next 18 months” to answer the following questions. “No” means that the student will not graduate in the next 18 months. “Yes” means that the student will graduate in the next 18 months.

Write the claim in symbolic form

a) Write the null and alternative hypothesis in symbolic form

b) State the test statistic

c) State the p-value

d) State your conclusion about the null hypothesis using a 0.05 significance level

e) Write a sentence to communicate to the administrator your conclusion about his claim