Res/342 E-Text

hebdomad 5 E-text
Ashley Gould
RES/342
May 8, 2012
Dr. James Smalls

Week 5 E-text
A. coefficient of correlational statisticsal statistics and linear regression atomic number 18 non the resembling. Consider these differences: Correlation quantifies the degree to which devil unsettleds are related. Correlation does not find a best-fit line (that Is regression). You simply are computing a correlation coefficient (r) that tells you how much unmatched variable tends to change when the other one does. With correlation you dont have to opine rough cause and effect. You simply quantify how well two variables relate to each other. With regression, you do have to think about cause and effect as the regression line is situated as the best way to predict Y from X .With correlation, it doesnt matter which of the two variables you call X and which you call Y. Youll get the same correlation coefficient if you change over the two. With linear regression, the conclusion of which variable you call X and which you call Y matters a lot, as youll get a different best-fit line if you swap the two. The line that best predicts Y from X is not the same as the line that predicts X from Y. Correlation is almost endlessly used when you measure both variables. It rarely is appropriate when one variable is something you experimentally manipulate.



With linear regression, the X variable is very much something you experiment tall manipulate (time, concentration...) and the Y variable is something you measure
B. correlation coefficient reveals the strength of the relationship between two variables
C. When the t get across is unavailable, a quick test for signifi thronece of a correlation at ? = .05 this quick rule is derived from formula 12.5 by inserting 2 in place of t?. It is based on the circumstance that two-tail t-values for ? = .05 usually are not far from 2, as you can verify from Appendix D. This quick rule is exact for ? = 60 and works reasonably well as long as n is not too small
D. This statistic measures the degree of linearity in the relationship...If you want to get a full essay, order it on our website: Ordercustompaper.com



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