Akshita (student) (108 Points)
03 June 20121. 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)
(1460 Points)
Replied 03 June 2012
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......
Tejaswi Kasturi
(student-cpt)
(427 Points)
Replied 04 June 2012
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
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