Let z denote the standard normal random variable.

a. Draw a graph of the standard normal distribution and shade the area associated to the value of Pr(-1 z 1). Using the Empirical Rule that we learned in class, what is the approximate value of Pr(-1 z 1)? Now using the methods we learned this week, find Pr(-1 z 1) to four decimal places of accuracy.

b. Using the Empirical Rule, what is the approximate value of Pr(-2 z 2)? Now using the methods we learned this week, find Pr(-2 z 2) to four decimal places of accuracy.