psyc 60 computation practice 7 with answers

psyc 60 computation practice 7 with answers - y ) 2 n =...

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For the following data:. .. compute the mean, median, and major mode of dataset A, treating it as a sample compute the range, I.Q. range, M.A.D., variance, and standard deviation of dataset A as a sample compute the correlation between the data sets (treating columns as pairs) determine the least squares linear regression equation treating dataset A as the X variable predict the value of dataset B if dataset A is 3 and give a standard error of the estimate Dataset A: 4 -5 -5 -3 4 -5 2 0 -2 3 0 Dataset B: 3 -14 -5 13 4 9 -2 10 17 -5 3 Averages: Sorted Data: -5 -5 -5 -3 -2 0 0 2 3 4 4 Major Mode: -5 Median: midpoint is datum number ( n +1) / 2 = 6, median is 0 Mean: ¯ x = x n = - 7 . 00 / 11 = -0.64 Variability: Variance and Standard Deviation: SS = s ( x 2 ) - ( x ) 2 n = 133 - 49 11 = 128 . 55 s 2 = SS n - 1 = 12.85 , s = 3.59 M.A.D. = | x - ¯ x | n = 3.06 Sorted Data: -5 -5 -5 -3 -2 0 0 2 3 4 4 Range: max - min = 4 - -5 = 9 Interquartile range: n + 3 4 = 3 . 5 so count o± 3 from each end , 3 -- 5 = 8 Correlation and Prediction: Correlation: SP xy = s ( xy ) - ( x )( y ) n = - 14 . 00 - ( - 7 . 00)(33 . 00) 11 = 7 . 00 SS y = s ( y 2 ) - (
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Unformatted text preview: y ) 2 n = 923-1089 11 = 824 . 00 SS x = s ( x 2 )-( x ) 2 n = 133-49 11 = 128 . 55 r = SP xy r SS x SS y = 7 . 00 r (128 . 55)(824 . 00) = 0.02 Regression: b = SP xy SS x = 7 . 00 128 . 55 = 0 . 05 Y = y n = 33 . 00 / 11 = 3 . 00 , X = x n =-7 . 00 / 11 =-. 64 a = Y-( b )( X ) = 3 . 00-(0 . 05)(-. 64) = 3 . 03 Y p = bX + a = Y p =(0.05)(X)+(3.03) Prediction: at x = 3, the prediction for y = (0 . 05)(3)+ 3 . 03 = 3.20 Standard Error of Prediction: s y | x = R SS y (1-r 2 ) n-2 = R 824 . 00(1-(0 . 02) 2 ) 11-2 = 9.57 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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This note was uploaded on 01/23/2011 for the course PSYC 60 taught by Professor Ard during the Fall '08 term at UCSD.

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