psyc 60 computation worksheet 4 with answers

# psyc 60 computation worksheet 4 with answers - 11 = 155 64...

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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 8 and give a standard error of the estimate Dataset A: 3 5 10 8 1 3 3 4 0 0 -1 Dataset B: 8 1 7 6 -1 8 11 1 3 1 8 Averages: Sorted Data: -1 0 0 1 3 3 3 4 5 8 10 Major Mode: 3 Median: midpoint is datum number ( n +1) / 2 = 6, median is 3 Mean: ¯ x = x n = 36 . 00 / 11 = 3.27 Variability: Variance and Standard Deviation: SS = s ( x 2 ) - ( x ) 2 n = 234 - 1296 11 = 116 . 18 s 2 = SS n - 1 = 11.62 , s = 3.41 M.A.D. = | x - ¯ x | n = 2.53 Sorted Data: -1 0 0 1 3 3 3 4 5 8 10 Range: max - min = 10 - -1 = 11 Interquartile range: n + 3 4 = 3 . 5 so count o± 3 from each end , 5 - 0 = 5 Correlation and Prediction: Correlation: SP xy = s ( xy ) - ( x )( y ) n = 199 . 00 - (36 . 00)(53 . 00) 11 = 25 . 55 SS y = s ( y 2 ) - ( y ) 2 n = 411 - 2809
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Unformatted text preview: 11 = 155 . 64 SS x = s ( x 2 )-( ∑ x ) 2 n = 234-1296 11 = 116 . 18 r = SP xy r SS x SS y = 25 . 55 r (116 . 18)(155 . 64) = 0.19 Regression: b = SP xy SS x = 25 . 55 116 . 18 = 0 . 22 ¯ Y = ∑ y n = 53 . 00 / 11 = 4 . 82 , ¯ X = ∑ x n = 36 . 00 / 11 = 3 . 27 a = ¯ Y-( b )( ¯ X ) = 4 . 82-(0 . 22)(3 . 27) = 4 . 10 Y p = bX + a = Y p =(0.22)(X)+(4.10) Prediction: at x = 8, the prediction for y = (0 . 22)(8)+ 4 . 10 = 5.86 Standard Error of Prediction: s y | x = R SS y (1-r 2 ) n-2 = R 155 . 64(1-(0 . 19) 2 ) 11-2 = 4.08 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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