Suppose that the talk time on a fully charged iPhone is approximately normally distributed with mean 7 hours and standard deviation 0.8 hour. (a) what is the probability that a fully charges iphone...

 Suppose that the talk time on a fully charged iPhone is approximately normally distributed with mean 7 hours and standard deviation 0.8 hour.

(a) what is the probability that a fully charges iphone will last less than 6 hours?

(b) Simple random samples of 16 fully charged iphones are obtained.  Describe the sampling distribution of x, the mean talk time of the sample.  In other words, comment on the shape, center (calculate the mean), and spread (calculate the standard deviation) of the distribution.

Shape:

Center:

Spread: