Course and Section Number Program of Study
STA 2014 Business

Statistics
STA2014
Week 10 Individual Work

Assignment Instructions
To complete this assignment:

1. Answer all of the questions below in the space provided.
2. Reflect on the information presented in this week’s lesson and provide an insightful response to each question.

Save and Submit to Dropbox
1. Save your work as a Microsoft Word 2010 (.docx) file that includes your name, course code, and title in the file name. For example: JaneSmith_STA2014_Week10.docx.
2. To submit your assignment, go to the Dropbox and click "Submit Assignment."
3. Click on the drop-down menu to select the Week 10: Individual Work basket in the Dropbox.

Objective: Use confidence intervals appropriately.

Section 9.1
22. You Explain It! Superstition: A USA Today/Gallup poll asked 1,006 adult Americans how much it would bother them to stay in a room on the 13th floor of a hotel. Interestingly, 13%said it would bother them. The margin of error was 3 percentagepoints with 95% confidence. Which of the following represents a reasonable interpretation of the survey results? For those not reasonable, explain the flaw.
(a) We are 95% confident that the proportion of adult Americans who would be bothered to stay in a room on the 13th floor is between 0.10 and 0.16.
Answer:

(b) We are between 92% and 98% confident that 13% of adult Americans would be bothered to stay in a room on the 13thfloor.
Answer:

(c) In 95% of samples of adult Americans, the proportion who would be bothered to stay in a room on the 13th floor is between 0.10 and 0.16.
Answer:

(d) We are 95% confident that 13% of adult Americans would be bothered to stay in a room on the 13th floor.
Answer:

Section 9.2
8. (a) Find the t-value such that the area in the right tail is 0.02 with 19 degrees of freedom.
Answer:

(b) Find the t-value such that the area in the right tail is 0.10 with 32 degrees of freedom.
Answer:

(c) Find thet-value such that the area left of thet-value is 0.05with 6 degrees of freedom.[Hint: Use symmetry.]
Answer:

(d) Find the critical t-value that corresponds to 95% confidence. Assume 16 degrees of freedom.
Answer:

Section 9.3
7. Aggravated Assault:In a random sample of 40 felons convicted of aggravated assault, it was determined that the mean length of sentencing was 54 months, with a standard deviation of 8 months. Construct and interpret a 95% confidence interval for the mean length of sentence for an aggravated assault conviction. Source: Based on data from the U.S. Department of Justice.
Answer:

12. Theme Park Spending: In a random sample of 40 visitors to a certain theme park,it was determined that the mean amount of money spent per person at the park (including ticket price) was $93.43 per day with a standard deviation of $15. Construct and interpret a 99% confidence interval for the mean amount spent daily per person at the theme park.
Answer:


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