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maths correlation and regression...urgent help needed...

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 Akshita student [ Scorecard : 93] Posted On 03 June 2012 at 13:08 1. if x and y satisfy the relationship y = -5 + 7x, the value of r is? 2. if the realtion between x and u is 3x + 4u + 7 = 0 and the coeffecient correlation between x and y is -0.6, then what is the correlation coeffecient between u and y? thnaks in advance.... intermediate(ipc)course no [ Scorecard : 1446] Posted On 03 June 2012 at 14:14 1. we know, r = root bxy * byx                         = root -5*-5                         =root 25                         =5 ans........   2. 3x+4u = -7 therefore c = 4/3 then, ruy = |c|rxy                 = |4/3|*-0.6                 =4/3 *-0.6                 = -0.8 ans......                                               Total thanks : 1 times Akshita student [ Scorecard : 93] Posted On 03 June 2012 at 15:26 thanks a lot... Tejaswi Kasturi student-cpt [ Scorecard : 402] Posted On 04 June 2012 at 13:05 1. Its impossible to know r with just regression equation b = r*sy/sx so without knowing standard deviation of x or y or snowing bxy we can't tell what r is byx here is 7 bxy is not given swati wrongly assumed the constant coeefficient a as byx and assumed it is equal to byx and correlation coefficient is always less than 1 2.in the second one for correlation we only take the signs of the3 relationship and not magnitude u = -0.75x - 1.75 so u and x are negatively correlated now x and y correlation is - so u and y correlation is 0.6 0.6 Total thanks : 1 times

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