Question

Time

3.3

6.6

4.9

6.1

0.4

10.5

18.3

3.7

4.2

6.5

0.1

Company A is trying to sell its website to Company B. As part of the sale, Company A claims that the average user of their site stays on the site for 10 minutes. To test this claim Company B collects the times (in minutes) below for a sample of 11 users. Assume normality.

Construct a 91% confidence interval for the true mean time spent on the web site.

a) What is the lower limit of the 91% interval? Give your answer to three decimal places. Enter 0 if your lower limit is less than 0.  

b) What is the upper limit of the 91% interval? Give your answer to three decimal places.  

c) Based on this data, do you believe the claim made by Company A?

-No because 10 is inside the interval.

-No because 10 is not inside the interval.    

-Yes because 10 is inside the interval.

-Yes because 10 is not inside the interval.

d) Which of the following assumptions should be checked before constructing the above confidence interval?

-the data need to be skewed

-the data need to follow a t distribution

-the data need to follow a normal distribution

-the data need to have small variance

Answer 1