Suppose that a big study conducted similarly to our cell phone survey determined that the time to send our 25-word

INSTRUCTIONS TO CANDIDATES

ANSWER ALL QUESTIONS

1. Suppose that a big study conducted similarly to our cell phone survey determined that the time to send our 25-word message was normally distributed with a mean of 31.6 seconds and a standard deviation of 11.4 seconds.

a. (5 pts.) Using the “big study” as the population, what is the probability that a randomly selected person would take more than 35 seconds to send the 25 word message? [5.2]

b. (5 pts.) At least how many seconds would you need to observe to conclude the time to send was unusually slow [5.3]

2. (5 pts.) I looked at our cell phone survey Time to Send data, combined male and female information, eliminated outliers and determined that there were 72 observations with a mean time to send of 28.4 seconds. Use the mean and standard deviation from the “big study” (population) in the prior problem and the Central Limit Theorem to determine if our sample mean time was unusually fast. Justify your answer! [5.4]

I’ve summarized some information from our cell phone survey in the table below. Use the data in the table for questions 3-5.

 

	Female	Male	Total
iPnone	40	21
Not iPhone	7	13
Total

3. (5 pts.) Find a 95% confidence interval for the population proportion of Females who use an iPhone. [6.3]

4. (5 pts.) Find a 95% confidence interval for the population proportion of Males who use an iPhone. [6.3]

5. (5 pts.) Is there an overlap in the confidence intervals for Females and Males? Would you be surprised if the actual population proportion of iPhone use for both Females and Males was 76%? Why or why not? [6.3]

6. A colleague said she thinks it would take the typical student at least 30 seconds to send the 25-word text message in our study. In our random sample of 72 respondents we observed they had a mean time of 28.4 seconds with a standard deviation of 9.5 seconds. Assume the underlying population is normally distributed. [7.3]

a. (5 pts.) At the α = 0.10 level of significance, is there evidence to support my colleague’s claim?

b. (5 pts.) At the α = 0.05 level of significance, is there evidence to support my colleague’s claim?

c. (5 pts.) Compare the two conclusions above. Does this suggest any further study? Why or why not?

Attachments:

Related Questions

. The fundamental operations of create, read, update, and delete (CRUD) in either Python or Java

CS 340 Milestone One Guidelines and Rubric  Overview: For this assignment, you will implement the fundamental operations of create, read, update,

. Develop a program to emulate a purchase transaction at a retail store. This  program will have two classes, a LineItem class and a Transaction class

Retail Transaction Programming Project  Project Requirements:  Develop a program to emulate a purchase transaction at a retail store. This

. The following program contains five errors. Identify the errors and fix them

7COM1028   Secure Systems Programming   Referral Coursework: Secure

. Accepts the following from a user: Item Name Item Quantity Item Price Allows the user to create a file to store the sales receipt contents

Create a GUI program that:Accepts the following from a user:Item NameItem QuantityItem PriceAllows the user to create a file to store the sales receip

. The final project will encompass developing a web service using a software stack and implementing an industry-standard interface. Regardless of whether you choose to pursue application development goals as a pure developer or as a software engineer

CS 340 Final Project Guidelines and Rubric  Overview The final project will encompass developing a web service using a software stack and impleme