Question

each of the dot plots shown represents the number of glue sticks brought in by each student for two classes, class a and class b. which statement best compares the standard deviations of the numbers of glue sticks brought in by each student for these two classes? a the standard deviation of the number of glue sticks brought in by each student for class a is less than the standard deviation of the number of glue sticks brought in by each student for class b. b the standard deviation of the number of glue sticks brought in by each student for class a is equal to the standard deviation of the number of glue sticks brought in by each student for class b. c the standard deviation of the number of glue sticks brought in by each student for class a is greater than the standard deviation of the number of glue sticks brought in by each student for class b. d there is not enough information to compare these standard deviations.

Explanation:

Step1: Recall SD concept

Standard deviation (SD) measures data spread. Lower SD means data is clustered around the mean; higher SD means more spread out.

Step2: Analyze dot plots

Class A has values 1–7, Class B has 14–20. Both dot plots have the same dot - distribution shape (symmetric, peak in the middle, same spread relative to their own ranges). So the spread of data around their means should be equal. Thus, their SDs are equal.

Answer:

B. The standard deviation of the number of glue sticks brought in by each student for class A is equal to the standard deviation of the number of glue sticks brought in by each student for class B.