Probability Histograms

What is the midpoint of the class with the greatest frequency?

The amount of time required for each of 100 mice to navigate through a maze was recorded. The histogram here shows the distribution of times, in seconds, for the 100 mice. Which of the following values is closest to the standard deviation of the 100 times?

• 2.5 seconds

• 10 seconds

• 20 seconds

• 50 seconds

• 90 seconds

• 25

• 15

• 5

• 10

• 63

• 56

• 53

• 43

• 32

• 33

• 44

• 38

• 43

• 57

• 41

• 59

• 36

• 45

• 27

• 35

• 17.5

• 15

• 30

• 25

• 30

• 18

• 36

• 23

• 95

• 5

• 57

• 3