# stats- confidence interval

**Question description**

A telecommunications company wants to estimate the mean length of time (in minutes) that 18 to 24 year olds spend text messaging each day. In a random sample of twenty seven 18 to 24 year olds, the mean length of time spent texting was 29 minutes. From past studies the standard deviationis 4.5 minutes. Find the 90% confidence interval.

1. Find the critical value

2. Find the margin of error: E =

3. Find the confidence interval: CI =

Write the conclusion.

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