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 470 with a standard deviation of 30 on a standardized test. Assuming a bell-shaped distribution, where would approximately 68% of the students score?
A) between 440 and 500
B) below 440 or above 500
C) below 410 or above 530
D) between 410 and 530

Question

Quizplus · Accepted Answer

In a bell-shaped (normal) distribution, approximately 68% of the data falls within one standard deviation of the mean. Here, the mean is 470 and the standard deviation is 30, so 68% of the scores would fall between 440 (470-30) and 500 (470+30).

A Study Was Designed to Investigate the Effects of Two