Question

If x1, x2, x3.... Xn are the means of n groups with n1, n2, n3,.... nn number of observations respectively then find the mean x of all the groups taken together

Answer 1

Mean of 7 observation = 32
Sum of 7 observation = 32×7 = 224
Added observation= 48
Sum of 8 obsarvation= 224+48= 272
Mean of 8 observation 272\8= 34

Answer 2

Answer:

mean of 7 observation= 32

sum of 7 observation =32×7=224

added observation =48

mean of 8 observation =224+48=272

sum of 8 observation = 272/8=34