A study was designed to investigate the effects of two variables - (1) a studentʹs level of mathematical anxietyand (2) teaching method - on a studentʹs achievement in a mathematics course. Students who had a low levelof mathematical anxiety were taught using the traditional expository method. These students obtained a meanscore of 460 with a standard deviation of 40 on a standardized test. Assuming a bell-shaped distribution,where would approximately 68% of the students score?
A) between 420 and 500
B) between 380 and 540
C) below 380 or above 540
D) below 420 or above 500

Question

Quizplus · Accepted Answer

Approximately 68% of the scores in a bell-shaped (normal) distribution fall within one standard deviation of the mean. Given a mean of 460 and a standard deviation of 40, 68% of the scores would fall between 420 (460 - 40) and 500 (460 + 40).

A Study Was Designed to Investigate the Effects of Two