According to the Internal Revenue Service, the average income tax refund for the 2011 tax year was $ 2,913. Assume the refund per person follows the normal probability distribution with a standard deviation of $ 950.

a. What is the probability that a randomly selected tax return refund from the 2011 tax year will be

1. More than $ 2,000?

2. Between $ 1,600 and $ 2,500?

3. Between $ 3,200 and $ 4,000?

b. Confirm the answers to part a using Excel or PHStat.

c. What refund amount represents the 35th percentile of tax returns?