JEE Main201815 Apr 2018Evening ShiftMathematicsStatisticsActual

If the mean of the data: 7,8,9,7,8,7, , 8 is 8 , then the variance of this data is

Options

A9 8
B2
C7 8
D1

Correct answer

D. 1

Step-by-step solution

aligned & x = 7+8+9+7+8+7+ +8 8 =8 & 54+ 8 =8 =10 aligned Now variance = ^2 aligned &(7-8)^2+(8-8)^2+(9-8)^2+(7-8)^2+(8-8)^2 &= +(7-8)^2+(10-8)^2+(8-8)^2 8 & ^2= 1+0+1+1+0+1+4+0 8 = 8 8 =1 & aligned Hence, the variance is 1 .

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