I NEED HELP BEFORE 4:30PM EST Fill in the blanks, the numbers you can use are:

3, -3, 56, 1, 8, 7, 15, -7

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?