Question

If the test scores of a class of 35 students have a mean of 74.3 and the test scores of another class of 28 students have a mean of 67.6, then the mean of the combined group is

Answer 1

Let the total sum of the scores of the first class of 35 students be a. The mean is 74.3 .

So

`(a)/(35)=74.3\\\\a=35\cdot74.3= 2600.5`

Also, let the total sum of the scores of the second class of 28 students be b. The mean is 67.6 .

so

`(b)/(28)=67.6\\\\ b=28\cdot67.6= 1892.8`



The combined group has 35+28=63 students. The sum of their scores is

a+b=2600.5+1892.8=4493.3


Thus, the mean of the combined group is
`(4493.3)/(63)= 71.32`