Question 971751: Two classes take a statistic exam. In the first class, 25 students had a mean score of 80. The two classes together had 40 students with a mean score of 83. Compute the mean score of the second class.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! mean = total/number
total= mean * number
total = 83*40 = 3320
But class of 25 had a mean of 80, so their total was 2000.
There are 15 in the other class, and their total had to be 1320.
The mean in the other class is 1320/15.
It equals 88.
Mean of class 1 was 80; class 2, smaller, had a mean of 88. The combined mean should be weighted closer to class 1, and it is.
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