Determine the area under the standard normal curve that lies to the left of (a) z= -1.11 (b) z= -1.06 (c) z= -1.13, and (d) z= -1.49

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?