Let's assume X is a random variable that represents the net income of the neighborhood lemonade stand. Notice that X can be a negative value, as in the example where they were spending more money than they were earning.

Let X be distributed as a Normal distribution with mean, mu = 50, and standard deviation, sigma = 30.

Using the empirical rule, what is Pr(X < -10)?

Using the empirical rule, what is Pr(-10 < X < 50)?

Using the empirical rule, what is Pr(20 < X < 110)?

Find the z-score for when x = 40.