Automobiles traveling on a road with a posted speed limit of 65 miles per hour are checked for speed by a state police radar system.The following is a frequency distribution of speeds. The mean speed of the automobiles traveling on this road is closest to:
A)55.0
B)57.8
C)64.1
D)65.0

Question

Automobiles traveling on a road with a posted speed limit of 65 miles per hour are checked for speed by a state police radar system.The following is a frequency distribution of speeds.  The mean speed of the automobiles traveling on this road is closest to:
A)55.0 
B)57.8 
C)64.1 
D)65.0

Quizplus · Accepted Answer

To find the mean speed, we need to multiply each speed by its frequency, add up these products, and divide by the total frequency. Using the frequency distribution table, we can calculate:

(50*1 + 55*2 + 60*4 + 65*7 + 70*4 + 75*2 + 80*1) / 21 ≈ 64.1

Therefore, the mean speed of the automobiles traveling on this road is closest to 64.1 miles per hour, which corresponds to choice C).

Automobiles Traveling on a Road with a Posted Speed Limit