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

23

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

3.

Complete parts (a) through (d) below.

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Part 1

a. If you select a random sample of

25

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

22.5

and

23.5?