Math homework

HOME WORK EXAMPLE 4. For a certain group of taxpayers who get refunds, the average amount of refund is $918. The standard deviation is $45. If 54 taxpayers are selected at random, find the probability that the refund is the following amount. (a) Between $910 and $930 (b) More than $925 EXAMPLE 5. Let Z be a random variable with a standard normal distribution. Find these probabilities. (a) P( Z