CORRELATION_07

# CORRELATION_07 - correlation in the population equals zero)...

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The Pearson’s Correlation Coefficient

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r = r can vary from +1 to -1 r=0 means no relationship +1 or -1 means perfect correlation positive (+) or negative (-) sign indicates the direction of the relationship numerical value indicates the strength of the relationship r 2 = coefficient of determination (proportion of variability in one variable that can be predicted from the relationship with the other variable)
Examples of positive & negative correlation

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Examples of different values for linear correlation
Restricted range problem

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Outlier problem
Things to remember: Correlation describes a relationship b/w two variables Pearson’s correlation measures a linear relationship Interpretation: Correlation does not imply causation For correlation to be accurate there should be a wide in the data - Restricted range problem - Outliers problem

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HYPOTHESIS TESTS WITH THE PEARSON CORR . H o : No, there is no correlation in the population (i.e.,

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Unformatted text preview: correlation in the population equals zero) H 1 : Yes, there is a real, nonzero correlation in population df for the Table: df= n-2 (n= sample size) Statistical significance and- strength of correlation - sample size SPSS printout Correlation b/w SELF ESTEEM &amp; MOTIVATION Degree of freedom (df = n-2) APA format for reporting r(8) = .65 , p&lt; .05 or r = .65, n = 10, p&lt; .05 SELFESTEEM MOTIVATION SELFESTEEM Pearson Corr. . Sig. (2-tailed) N 1.000 . 10 . 647* .05 10 MOTIVATION Pearson Corr. . Sig. (2-tailed) N .647* .05 10 1.000 . 10 The Best-fit Line REGRESSION EQUATION The best fitting straight line describes the relationship b/w two variables (= regression line ) It has a general form of Y = b *X + a b = slope (constant) a = Y intercept (constant) It can be used for prediction The stronger the correlation between X &amp; Y the more accurate prediction of regression equation...
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## This note was uploaded on 11/12/2009 for the course PSY 3301 taught by Professor Staff during the Fall '08 term at Texas State.

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CORRELATION_07 - correlation in the population equals zero)...

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