Question

The mean of 12 observation is 65.later on it was observed that 75 was misread as 57 .find the correct mean.

Answer 1

$\huge\mathbb{SOLUTION:-}$

Given the means of 12 observation is 65

Now

$\sf\underline{\red{A.T.Q:-}}$

$\sf let\: observation\:be\:x_1\:x_2......x_12$

$\sf 65=\dfrac{x_1+x_2+x_3.......x_{12}}{12}\\ \\ \sf\implies 65\times 12=x_1+x_2+x_3+........x_12\\ \\ \sf \implies 780=x_1+x_2+x_3....x_{12} \\ \\ \sf\:\: 1\: observation\:75\: misread\:as 57\\ \\ \sf\bullet 780-57+75\\ \\ \sf \bullet 780+18=798$

• Now new mean

$\sf\:\:\dfrac{798}{12}\\ \\ \sf\implies mean= 66.5$

So our new mean will be 66.5

Answer 2

The correct mean is 798.

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