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 370 with a standard deviation of 20 on a standardized test. Assuming no information concerning the shape of the distribution is known, what percentage of the students scored between 330 and 410?
A) at least 75%
B) approximately 95%
C) at least 89%
D) approximately 68%

Question

Quizplus · Accepted Answer

According to Chebyshev's theorem, at least 75% of data falls within two standard deviations of the mean for any distribution. Here, 330 and 410 are two standard deviations away from the mean of 370.

A Study Was Designed to Investigate the Effects of Two