Question

The two dot plots below compare the forearm lengths of two groups of schoolchildren:

Based on visual inspection of the dot plots, which of the following groups appears to have the longer average forearm length?

A. Group A, because no child in the group has a forearm length longer than 11 inches

B. Group B, because two children have a forearm length longer than 11 inches

C. Group A, because three children in the group have the least forearm length of 9 inches

D. Group B, because a child in the group has the least forearm length of 9 inches

Answer 1

The correct option is B.

Explanation:

From the given dot plot we can say that 3 children have 9 in. long forearm, 4 children have 10 in. long forearm and 3 children have 11 in. long forearm.

The average of length of forearms of Group A is

The average of length of forearms of Group A is 10 inches.

From the given dot plot we can say that 3 children have 10 in. long forearm, 5 children have 11 in. long forearm and 2 children have 12 in. long forearm.

The average of length of forearms of Group B is

The average of length of forearms of Group B is 10.9 inches.

10.9>10 it means Group B has longer average forearm length. It is true because two children have a forearm length longer than 11 inches.

Therefore the correct option is B.