Study Guides (248,217)
Canada (121,408)
Psychology (1,882)
PSYB07H3 (20)
Final

EXAM REVIEW CORRELATION COEFFICIENT.doc

4 Pages
146 Views
Unlock Document

Department
Psychology
Course
PSYB07H3
Professor
Douglas Bors
Semester
Fall

Description
AFTER MIDTERM EXAM NOTES PEARSON-PRODUCT MOMENT CORRELATION COEFFICIENT (r) -tells us the strength of the relationship between x and y -the average product of z-scores  same thing as z scores -correlation coefficients are the covariance when there are standard variables  standardize x but leave y and its use  get a measure in y units COV xya measure of the relation between x and y  the covariance standardized by the standard deviation of x and y -o standardize , we divide the covariance by the size of the standard deviations. -g iven that the maximum value of the covariance is plus or minus the product of the variance of x and the variance of y, it follows that the limits on the correlation coefficient are +1.0 or – 1.0 -the correlation coefficient is not an unbiased esimator C O V r = x y sxy If the regression coefficient is computed the slopes can be he same but the correlation is different i.e. the second scatterplot has more noise. Example: x- y- 3 4 9 4 4 1 10 1 5 0 12 1 6 1 11 0 7 4 13 4 xy=1 1 sy=1.5 8 x =5 x s =1.5 8 x 1. C x = yO.2 5 V 2. C x y O V r = sxsy 2.2 5 r = (1.5 ) 1.) ( 8 r = 0.9 3. 2 r = 1− (1− r ) N ( 1) a d j (N − 2) (1−.8 ) −11) 5 ra= d− j ( − 25) = .75 -expected value of r is not ρ (rho --> Greek letter), then we correct for it -correlation cannot = 1 because there will be many variables that affect (influence) relationship of behaviour you’re trying to predict r = that proportion of the variance is y that is shared (accounted for) by x. Sometimes called “coefficient of determination” 2 -therefore, r = 0.9 and r = 0.81 or x account for 81% of the variance in y
More Less

Related notes for PSYB07H3

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit