Suppose it is known that the distribution of purchase amounts by customers entering a popular retail store is approximately normal with mean $25 and standard deviation $8.
a. What is the probability that a randomly selected customer spends less than $35 at this store?
b. What is the probability that a randomly selected customer spends between $15 and $35 at this store?
c. What is the probability that a randomly selected customer spends more than $10 at this store?
d. Find the dollar amount such that 75% of all customers spend no more than this amount.
e. Find the dollar amount such that 80% of all customers spend at least this amount.
f. Find two dollar amounts, equidistant from the mean, such that 90% of all customer purchases are between these values.