find the mean of the data summarized in the given frequency distribution. Compare and computed mean to the actual mean of 51.9 miles per hour: speed (miles per hr XXXXXXXXXXFrequency 42-45...

find the mean of the data summarized in the given frequency distribution. Compare and computed mean to the actual mean of 51.9 miles per hour:
speed (miles per hr) Frequency
42-45 21
46.49 12
50-53 7
54-57 4
58-61 2
The mean of the frequency is _____
What is the relationship between the computed mean and the actual mean?