Q3 of 33 Page 156

Mean of eight observations is 25. If one observation 11 is excluded, find the mean of the remaining.

Given, Mean of 8 observations is 25.

Clearly, No of observations, n = 8 and mean,


We know,


Arithmetic mean of x1, x2, x3, …, xn (n observations) is





⇒ sum of terms is 200.


If one observation 11 is excluded,


No of terms = 7


Sum of terms = 200 - 11 = 189




Hence, new mean is 27.


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