The batteries from a certain manufacturer have a mean lifetime of

Question

890
hours, with a standard deviation of
90
hours. Assuming that the lifetimes are normally distributed, complete the following statements.

Answer 1

What statements? You cannot copy and paste here.

Just guessing:

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to your Z scores.