Exercises_on_Regression

Exercises_on_Regression - (b) John and Will score 485 and...

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February 3, 2010 Exercises on Regression and Prediction Multiple- Choice questions #1 The amount of regression toward the mean is least when r is a. low. b. high. c. negative. d. positive. #2 Which value of r permits the greatest accuracy of prediction? a. +.78 b. +.27 c. -.37 d. -.81 Fill- In Questions #1 The _________ reflects the angle and direction of the regression line. #2 The higher the correlation, the __________ the prediction error. #3 The ________________ is the one that minimizes the sum of the squares of the discrepancies between the actual value of Y and the predicted value.
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Problems #1 The following data are for freshman students at Rochester University: APTITUDE SCOE: X FRESHMAN GPA: Y Mean of X = 560 Mean of Y = 2.65 SDx = 75 SDy = .35 r = +.50 (a) Write the regression equation for predicting Y from X.
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Unformatted text preview: (b) John and Will score 485 and 710, respectively, on the aptitude test. Predict the freshman GPA for each. (c) What assumption is necessary for this prediction to be valid? #2 A researcher was interested in the effect of stress level on the quality of marital interaction. She measured stress level and then observed the number of times a spouse spoke sharply during a two-hour test period, producing an irritability score. The fictional data from 4 participants are as follows: X Y Subject (Stress level) (Irritability) 1 4 10 2 10 15 3 2 7 4 6 7 Mx = 5.5 My = 9.75 Sx = 2.96 Sy = 3.27 r = 0.81 (a) Give the prediction formula for predicting the irritability from stress level (b) Predict the irritability level for someone with a stress level of 9...
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Exercises_on_Regression - (b) John and Will score 485 and...

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