Question 1037848
Find the mean and the standard deviation of the age (correct to 3 sig fig):
Age (x)   c.c   f
20<x<=30  25    6
30<x<=40  35    10
40<x<=40  45    9
50<x<=60  55    4
60<x<=70  65    1
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Using the "Mark" of each interval as its representative value
mean = 39.667
std = 10.743
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Cheers,
Stan H.
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