The Average Cost of Tuition, Room and Board at Community

The average cost of tuition, room and board at community colleges is reported to be $8,500 per year, but a financial administrator believes that the average cost is higher. A study conducted using 150 community colleges showed that the average cost per year is $9,000 with a standard deviation of
$1,200. Let α = 0.05.
Given the z-statistic is 5.1, what is our decision about the average cost?

A) Equal to $8,500
B) Greater than $8,500
C) Less than $8,500
D) Not equal to $8,500
E) None of these statements are true