Chapter 6, Problem 2PS

Given a standard normal distribution (with a mean of 0 and a standard deviation of 1, as in Table E.2), What is the probability that

$\begin{array}{l}\text{a}\text{.}\text{Z}\text{is}\text{between}-1.57\text{and}1.84?\\ \text{b}\text{.}Z\text{is}\text{less}\text{than}-1.57\text{or}\text{greater}\text{than}1.84?\\ \text{c}\text{.}\text{what}\text{is}\text{the}\text{Value}\text{of}Z\text{if}\text{only}2.5\text{percent}\text{of}\text{all}\text{possible}Z\text{values}\text{are}\text{larger?}\\ \text{d}\text{.}\text{Between}\text{what}\text{two}\text{values}\text{of}\text{Z}\text{(symmetrically}\text{distributed}\text{around}\text{the}\text{mean)}\text{will}\text{68}\text{.26}\text{percent}\text{all}\text{possible}\text{Z}\text{Values}\text{be}\text{contained?}\end{array}$