Korelacija in regresija - Oddelek za psihologijo - Univerza v Ljubljani

X Y X-M(X) Y-M(Y) (X-M(X))(Y-M(Y))6 3 1 -3 -39 10 4 4 164 7 -1 1 -12 4 -3 -2 64 6 -1 0 0M 5 6 0 0 3,6SD 2,366432 2,44949 2,366432 2,44949 kovariancaPoročanje• „Prepričanje, da se bodo šli naslednje leto cepit protigripi, je s starostjo naraščalo, r = 0,65.“• Korelacijske matrike:5*X 10*Y X-M(X) Y-M(Y) (X-M(X))(Y-M(Y))30 30 5 -30 -15045 100 20 40 80020 70 -5 10 -5010 40 -15 -20 30020 60 -5 0 0M 25 60 0 0 180SD 11,83216 24,4949 11,83216 24,4949 kovariancakovarianca = 3.6 * 5 * 10Vedno enako vrednost bi dala enačbacov XYSD SDXY… = enačba za rVelikost učinkaOdstotek pojasnjene variance0,10 - nizek r0,30 - srednje visok r0,50 - visok rr =.60r =1.00r 2 = 0 r 2 = .36r 2 = 1.00koeficient determinacijeFigure 15-8 (p. 425)Three sets of data showing three different degrees of linear relationship.Essentials of Statistics for the Behavioral Sciences, 5/E by Frederick J Gravetter and Larry B. WallnauCopyright © 2005 by Wadsworth Publishing, a division of Thomson LearningTežave pri interpretaciji rVpliv omejenosti obsegakorelacija in vzročnostFigure 15-6 (p. 423)(a) In this example, the full range of X and Y values shows a strong, positivecorrelation, but the restricted range of scores produces a correlation near zero.(b) Here the full range of X and Y values shows a correlation near zero but thescores in the restricted range produce a strong positive correlation.Essentials of Statistics for the Behavioral Sciences, 5/E by Frederick J Gravetter and Larry B. WallnauCopyright © 2005 by Wadsworth Publishing, a division of Thomson Learning3