If the standard deviation of 10 observations x_1,x_2 , ..... x_{10} is 4 and that of another set of10 observations y_1,y_2 , ..... , y_{10} is 3 and also X_i = (x_i-x^{-}) (y_i-y^{-}) . x^{-} is mean of all x_i ' s and y^{-} is mean all y_i ' s . \sum^{10}_{i=1} = 80 . Then standard deviation of observations x_1-y_1 , x_2-y_2 , .... x_{10}-y_{10} is

JEE Mains Model Paper 24

Question : 90 of 90

Marks: +1, -0

If the standard deviation of 10 observations x1,x2 , ..... x10 is 4 and that of another set of10 observations y1,y2 , ..... , y10 is 3 and also Xi = (xi−

−

) (yi−

−

) .

−

is mean of all xi ' s and

−

is mean all yi ' s .

i=1

= 80 . Then standard deviation of observations x1−y1 , x2−y2 , .... x10−y10 is

1
3
5
√5

Validate

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