AP EAMCET Engineering 21 Apr 2019 Shift 2 Paper

The standard deviations of xi (i = 1 , 2 , ... , 10) and yi (i = 1 , ... , 10) are respectively 'a' and 'b'

→

x

,

→

y

are the means of these two sets of observations respectively. If zi = (xi−

−

x

)(yi−

−

y

) and

10

Σ

i=1

zi = c , then the standard deviation of the observations (xi−yi) , (i = 1 , 2 , .. , 10) is