According to a report from a business intelligence company, smartphone owners are using an average of

24

apps per month. Assume that number of apps used per month by smartphone owners is normally distributed and that the standard deviation is

4.

Complete parts (a) through (d) below.

a. If you select a random sample of

36

smartphone owners, what is the probability that the sample mean is between

23.5

and

24.5?

0.4950.495

(Round to three decimal places as needed.)

b. If you select a random sample of

36

smartphone owners, what is the probability that the sample mean is between

23

and

24?

0.4090.409

(Round to three decimal places as needed.)

c. If you select a random sample of

100

smartphone owners, what is the probability that the sample mean is between

23.5

and

24.5?