Question

A simple random sample of 12 iPhone's being sold over the Internet had the

Answer 1

Answer:

The upper bound is 399.5

Step-by-step explanation:

Let's start by calculating the mean value of the distribution as the addition of all values given divided by 12:

Average = 289.75.

If the standard deviation is 56, then the upper bound in 95% the confidence interval for the mean price of the phones is going to be given by the mean value added to 56 times 1.96 (since 95% of the population is withing 1.96 times the standard deviation)

That is: 289.75 + 56 * 1.96 = 399.51

which rounded to one decimal place gives: 399.5