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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

Respuesta :

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

So 
[tex]\frac{a}{35}=74.3\\\\a=35\cdot74.3= 2600.5[/tex]

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

so 
[tex] \frac{b}{28}=67.6\\\\ b=28\cdot67.6= 1892.8[/tex]



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 [tex] \frac{4493.3}{63}= 71.32[/tex]

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