Suppose that a STAT150 student randomly sampled 500 American high school students to study SAT math scores. The math scores were distributed normally ("bell-shaped"), and the sample average was X ? 480 with a standard deviation of s = 60.
a) Sketch a picture of these data, and make sure to label the axis to show the values that deviate 1, 2, and 3 standard deviations away from the mean.
b) What percentage of students scored between 420 and 540?
c) What percentage of students scored between 480 and 540?
d) What percentage of students scored above 660?