# The Correlation Coefficient

 Who created the Product-Moment Correlation Coefficient? Karl Pearson What is the correlation coefficient? A model dependent measure of the strength of relationship between two variables It provides an appropriate measure of the strength of a relationship only within the context of linear regression What happens if the relationship between variables is non linear? The use of the correlation as a descriptive statistic is misleading What does the interpretation of the coefficient assume? An underlying bivariate normal distribution Normally distributed condition distributions Homogeneity of variance What are the relationship denotations for the correlation coefficient? When there is a perfect positive linearrelationship, r = 1.0 When there is perfect negative linearrelationship, r = -1.0 When r = 0.0 there is either no relationship,(or possibly a non-linear relationship) What is the probability formula for the coeffient? The square root of r2If the regression coefficient is negative the r value should also be made negativeThis means the correlation coefficient is the square root of the proportion of variability accounted for by the straight line regression What must be remembered when using R2? R2 must be expressed as a proportion when taking the square root (not a percentage)r varies between -1.0+1.0 whereas R2 varies between 0.0+1.0 Give a formula to relate the correlation coefficient to the regression coefficient r= slope x the square root of the sum of squares of x over the sum of squares of y What happens if X and Y are converted into standard scores (M=0.00, SD=1.0) The value of the coefficient will not be affected The SD will be the same for both Authorcamturnbull ID297182 Card SetThe Correlation Coefficient Description. Updated2015-03-01T15:22:50Z Show Answers