Below is a sorted stem-and-leaf diagram for the measured speeds (miles per hour)of 49 randomly chosen vehicles on highway I-80 in Nebraska.Which is the modal class?
A)60 but less than 70
B)70 but less than 80
C)80 but less than 90
D)impossible to determine

Question

Below is a sorted stem-and-leaf diagram for the measured speeds (miles per hour)of 49 randomly chosen vehicles on highway I-80 in Nebraska.Which is the modal class? 
A)60 but less than 70 
B)70 but less than 80 
C)80 but less than 90 
D)impossible to determine

Quizplus · Accepted Answer

The modal class is the class with the most frequency. In this stem-and-leaf plot, we can see that the digits in the tens place are the stems, and the digits in the ones place are the leaves. The class with the highest frequency is 7, which corresponds to the leaf 0 in the stem 7. Therefore, the modal class is the class of speeds from 70 mph to less than 80 mph, which is represented by the stem 7 and the leaves 0, 1, 2, 3, 4, 5, 6, and 8.

Below Is a Sorted Stem-And-Leaf Diagram for the Measured Speeds