Unformatted text preview: ( ∑ y ) 2 n = 1821296 9 = 38 . 00 SS x = s ( x 2 )( ∑ x ) 2 n = 118400 9 = 73 . 56 r = SP xy r SS x SS y = 11 . 00 r (73 . 56)(38 . 00) = 0.21 Regression: b = SP xy SS x = 11 . 00 73 . 56 = 0 . 15 ¯ Y = ∑ y n =36 . 00 / 9 =4 . 00 , ¯ X = ∑ x n =20 . 00 / 9 =2 . 22 a = ¯ Y( b )( ¯ X ) =4 . 00(0 . 15)(2 . 22) =3 . 67 Y p = bX + a = Y p =(0.15)(X)+(3.67) Prediction: at x = 8, the prediction for y = (0 . 15)(8)+3 . 67 =4.86 Standard Error of Prediction: s y  x = R SS y (1r 2 ) n2 = R 38 . 00(1(0 . 21) 2 ) 92 = 2.28 Note: On the exam you should round all intermediate results to 2 decimal places. However the fnal answers on this key were computed using higher precision, thereFore there may be rounding discrepancies with solutions computed rounding at every step, especially For prediciton....
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 Fall '08
 Ard
 Statistics, Normal Distribution, Regression Analysis, Standard Deviation, major mode

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