Psyc_315_-Winter_2010_-_Class_10

# Psyc_315_-Winter_2010_-_Class_10 - Recap of Last Class...

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1 Recap of Last Class • Regression Equation and Raw Scores • Explained and Unexplained Variation • Coefficient of determination and non- determination. • Questions? Chapter 8 Prediction and Regression In Practice 3 Example 1 • A psychologist wants to see if having extra days off in a month improves the happiness of factory workers. a) draw the scatter plot, and describe the relationship. b) calculate correlation. c) calculate coefficient of determination X = No. Days off Y = Happiness 3 3 3 6 6 9 7 9 7 10 9 9 9 10 9 10 10 10

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4 Scatterplot • Scatterplot shows a positive linear relationship between number of days off and level of worker’s happiness. • Can proceed to finding Pearson r. 0 2 4 6 8 10 12 0 2 4 6 8 10 12 Days Off Happiness 5 Pearson r X X-M (X-M) 2 Y Y-M (Y-M) 2 X – Xm)(Y – Ym) 3 -4 16 3 -5.44 29.59 21.76 3 -4 16 6 -2.44 5.95 9.76 6 -1 1 9 0.56 0.31 -0.56 7 0 0 9 0.56 0.31 0 7 0 0 10 1.56 2.43 0 9 2 4 9 0.56 0.31 1.12 9 2 4 10 1.56 2.43 3.12 9 2 4 10 1.56 2.43 3.12 10 3 9 10 1.56 2.43 4.68 M X = 7 = 54 M Y = 8.44 = 46.19 = 43 7 54 2.45 9 X X M SD = = = 8.44 46.22 2.27 9 Y Y M SD = = = r = ( X - X )( Y - Y )/ n S X S Y = Cov S X S Y 6 Pearson r r = ( X - X )( Y - Y ) / n S X S Y = Cov
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## This note was uploaded on 04/29/2010 for the course PSYCH 315 taught by Professor Afroditipanagopoulos during the Winter '10 term at Concordia Canada.

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Psyc_315_-Winter_2010_-_Class_10 - Recap of Last Class...

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