Question

two different math - classes took the same test and got the following results. class a: mean score = 80, standard deviation = 4. class b: mean score = 80, standard deviation = 9. which of the following is the best interpretation of these results? 1) students in class a did better on average than students in class b. 2) students in class b did better on average than students in class a. 3) scores in class a are generally closer to 80, while scores in class b vary more. 4) scores in class b are generally closer to 80, while scores in class a vary more.

Explanation:

Step1: Understand mean and standard - deviation

The mean represents the average score. Class A has a mean of 80 and Class B has a mean of 80, so on average, students in both classes perform the same. The standard - deviation measures the spread of the data. A smaller standard - deviation means the data points are closer to the mean. Class A has a standard - deviation of 4 and Class B has a standard - deviation of 9.

Step2: Analyze the options

Option A is incorrect because the means are the same, so students in neither class did better on average. Option B is also incorrect for the same reason. Option C is incorrect because the mean of both classes is 80, not 60. Option D is correct because a standard - deviation of 4 (Class A) indicates that scores are generally closer to 80, while a standard - deviation of 9 (Class B) means scores vary more.

Answer:

D. Scores in Class A are generally closer to 80, while scores in Class B vary more.