Question

Problem 3.

A study was designed to investigate the effects of two variables -- (1) a student's level of mathematical anxiety and (2) teaching method -- on a student's achievement in a mathematics course. Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 450 with a standard deviation of 30 on a standardized test. Suppose there are 500 students in the sample.

a) If the sample is normal, what percentage of scores was less than 390? Also estimate the number of students on that interval.

b) If the sample is unknown to be normal, estimate the percentage of scores between 360 and 540? Also estimate the number of students on that interval.

Answer 1