Question

Find the mean of the data summarized in the given frequency distribution.

12) The highway speeds of 100 cars are summarized in the frequency distribution below.  Find the mean speed.  

Speed (mph) Cars
30-39 4
40-49 19
50-59 50
60-69 15
70-79 12

 

A) 61.3 mph

B) 58.5 mph

C) 55.7 mph 

D) 54.5 mph

 

I said, D, and it is wrong.  

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