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If u = `(x  "a")/"c"` and v = `(y  "b")/"d"`, then b_{xy} = ______
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Solution
`"c"/"d"` b_{uv}
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b_{yx} = `square`
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when x = 10,
`y  square = square (10  square)`
∴ y = `square`
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4  8  32  16  64 
8  7  `square`  64  49 
Total = 30  Total = 40  Total = `square`  Total = 220  Total = `square` 
b_{xy} = `square/square`
b_{yx} = `square/square`
∴ Regression equation of x on y is `square`
∴ Regression equation of y on x is `square`
b_{xy} . b_{yx} = ______.