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 440 with a standard deviation of 50 on a standardized test. Assuming a mound-shaped and symmetric distribution, in what range would approximately 68% of the students score?
A) above 490
B) between 390 and 490
C) below 390 and above 490
D) below 490

Question

Quizplus · Accepted Answer

Approximately 68% of the data in a normal distribution falls within one standard deviation of the mean. Here, the mean is 440 and the standard deviation is 50, so the range is 440 ± 50, which is 390 to 490.

A Study Was Designed to Investigate the Effects of Two