Scores on IQ tests have a symmetric distribution that is roughly bell-shaped. Reported IQs are scaled so that the distribution has a mean of 100 and a standard deviation of 15. Suppose that a standard IQ test is given to 2000 students. Use the 68-95-99.7% Rule to answer the following:
a. About how many students in the group will have an IQ between 70 and 130?
b. About how many students in the group will have an IQ between 100 and 130?
c. About how many students in the group will have an IQ greater than 145? Hint: Find the approximate number between 55 and 145 first.