Question

A set of 10 values had arithmatic mean 20.find the arimthmatic mean if each values is doubled

Answer 1

Mean = $\frac{x1 + x2 +x3----x10}{10}$

20 = $\frac{x1 + x2 + x3-----x10}{10}$

20 × 10 = x1 +x2 + x3 ----x10 

200 = x1 + x2 + x3----x10

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If all values get doubled, 

Mean = $\frac{2(x1) + 2(x2) +2(x3) ----2(x10)}{10}$

Mean = $\frac{2[x1 + x2+x3---x10]}{10}$

Mean = $\frac{2 * 200}{10}$

Mean = $\frac{400}{10}$

Mean = 40




i hope this will help you



-by ABHAY

Answer 2

Hii friend,

Let the observations are Y1 , Y2 , Y3 , Y4 , Y5 , Y6 , Y7 , Y8 , Y9 , Y10.

Mean of the observations =Sum of observations /Number of observations

20 = Y1+Y2+Y3+Y4+Y5+Y6+Y7+Y8+Y9+Y10/10

Y1+Y2+Y3+Y4+Y5+Y6+Y7+Y8+Y9+Y10 = 20×10

Y1+Y2+Y3+Y4+Y5+Y6+Y7+Y8+Y9+Y10 = 200

Observations is to be double . Therefore New observations are :- 2(Y1) , 2(Y2) , 2(Y3) , 2(Y4) , 2(Y5) , 2(Y6) , 2(Y7) , 2(Y8) , 2(Y9) , 2(Y10).

New mean = Sum of Observations / Sum of observations.

New mean = 2(Y1) + 2(Y2) + 2(Y3)......+ 2(Y10)/10

New mean = 2[ Y1+Y2+Y3.....+Y10] /10

New mean = 2×200/10

New mean = 40

Hence,

The mean = 40

HOPE IT WILL HELP YOU...... :-)