The Statistical Abstract of the United States, published by the U.S. Census Bureau, reports that the average annual consumption of fresh fruit per person is 99.9 pounds, with a standard deviation of about 30 pounds. Suppose a researcher took a random sample of 38 people and had them keep a record of the fresh fruit they ate for one year.

a. What is the probability that the sample average would be less than 90 pounds?

(Note: Round all z values to 2 decimal places and your final answer to 4 decimal places.)