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Consider the number 1,2,3,4,5,6,7,8,9 and 10.If 1 is added to each number the variance of the number so obtained is

A

6.5

B

2.87

C

3.87

D

8.25

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The correct Answer is:D


Given number are 1,2,3,4,5,6,7,8,9, 10 and 11
Σxi=2+3+4++11
=102[2×2+9×1]=5[4+9]=65
Σx2i=22+32+42+52+.+112
=(12+22+33+.+112)(12
=11×12×2366=505
s2=Σ2in(Σxin)2=50510(6510)2
=505(6510)2
505(6.5)2
50.542.25
=8.25

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Updated on:21/07/2023

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