If the mean of x1, x, is 7.5, and the mean of x1, X2, x3 is………….
Solution:
Mean = sum of variables/number of variables.
First equation
X1 + X2 = 7.5
2
X1 + X2 = 15 —— (1)
Second equation
X1 + X2 + X3 = 8
3
X1 + X2 + X3 = 24 ——– (2)
Subtract equation 1 from equation 2
(X1 + X2 + X3) – (X1 + X2) = 24 – 15
X3 = 9
(a) 9 is correct
If each observation of the data is increased by 5, then their mean…………
Solution:
(d) is increased by 5 is correct
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