Question

1. Jessica wants to make a mobile phone application for her university, which has a student population of 6750. However, she only has enough time to develop either an Android app or an iOS app. To help her make a decision, she needs to estimate the proportion of Android phone users among the student population (Every student is either an Android phone user or an iPhone user). She randomly selects 35 students from the university records and finds that 21 of them are using Android phones.

Construct a 98% confidence interval for the proportion of android phone users among the student population.

Select one:

a. (0.386, 0.813)

b. (0.438,0.762)

c. (0.407,0.792)

d. (0.412,0.945)

2. Write a sentence interpreting your confidence interval, in the context of the problem.

3. Does the true proportion of Android phones differ from 0.5 at the α=0.05α=0.05 level?

Select one:

a. No, because the confidence interval contains 0.5

b. Yes, because the confidence interval contains 0.5.

c. Yes, because the sample proportion p̂ =0.6p^=0.6 is greater than 0.5

d. No, because the sample size is not big enough

4. Suppose Jessica wishes to repeat her study at a new university. Which of the following must be true about the confidence interval she will calculate?

Select one:

a. It must be computed based on a representative sample to be valid

b. If it is computed correctly, it should contain the true population parameter

c. The sample size needs to be greater than or equal to 30

d. All of the above

Answer 1