Question

value: 2
the table shows the quiz scores from two different classes. which of the following statement is true regarding the spread of the data?

2nd period quiz scores	4th period quiz scores
70	60
90	90
65	50
90	75
100	90
80	55
90	100
75	90
95	75
75	90
95	70
100	65
60	95
65	65
75	100

○ a. the mean score in the 2nd period class is about 81.6, and the mean score in the 4th period class is about 78.4. so on average, students in the 2nd period class performed better on the quiz.
○ b. the mean score in the 2nd period class is about 81.6, and the mean score in the 4th period class is about 78.4. so on average, students in the 4th period class performed better on the quiz.
○ c. the standard deviation of the scores for the 2nd period class is about 13.00, and the standard deviation of the scores for the 4th period class is about 16.20. so the data are more tightly clustered about the mean for the 4th period class.
○ d. the standard deviation of the scores for the 2nd period class is about 13.00, and the standard deviation of the scores for the 4th period class is about 16.20. so the data are more tightly clustered about the mean for the 2nd period class.

Explanation:

Step1: Recall standard - deviation concept

A smaller standard - deviation means data is more tightly clustered around the mean.

Step2: Analyze given standard - deviations

The standard deviation of the 2nd period class is about 13.00, and for the 4th period class is about 16.20. Since 13.00 < 16.20, the data for the 2nd period class is more tightly clustered around the mean.

Answer:

d. The standard deviation of the scores for the 2nd period class is about 13.00, and the standard deviation of the scores for the 4th period class is about 16.20. So the data are more tightly clustered about the mean for the 2nd period class.