If 16 Pr-1 : 15 Pr-1 = 16 : 7 then find r.
We know that nPr = n !/( n − r )! So, 16 Pr − 1 : 15 Pr − 1 = 16 : 7 = [ 16 !/ 16 −( r − 1 )!]÷[ 15 !/ 15 −( r − 1 )]= 16 ÷ 7 16 ÷ (17 – r) = 16 ÷ 7 17 – r = 7 Hence r = 10.
Let X and Y represent prices in Rs of a commodity in Kolkata and Mumbai respectively. It is given X(bar) = 65, Y(bar) = 67, standard deviation of X = 2.5, standard deviation of Y = 3.5 and r(x,y) = 0.8. What is the equation of regression of y on x?