Six students from a psychology class reported the number of hours of television they watch per week. Here are their data: 12, 15, 14, 13, 11. What is the standard deviation of the number of hours of television watched per week for this sample of 5 students?

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?