Given the following distribution of quiz scores for a statistics course:
87, 91, 74, 73, 80, 84, 68, 75
What is the standard deviation?
A)2.71
B)2.60
C)6.11
D)7.35

Question

Quizplus · Accepted Answer

The standard deviation is calculated by finding the square root of the variance. First, calculate the mean (average) of the scores: (87 + 91 + 74 + 73 + 80 + 84 + 68 + 75) / 8 = 79. Then, find the variance by averaging the squared differences from the mean: [(87-79)^2 + (91-79)^2 + (74-79)^2 + (73-79)^2 + (80-79)^2 + (84-79)^2 + (68-79)^2 + (75-79)^2] / 8 = 54.25. The square root of 54.25 is approximately 7.36, which rounds to 7.35, making D the correct answer.

Given the Following Distribution of Quiz Scores for a Statistics