correlations discussion

correlations discussion Computing the Pearson Correlation Coefficient The easiest manual way to compute the correlation between two variables is through the use of the raw score method. The formula for rxy (where xy represents the correlation between X and Y) is as follows: The Pearson correlation coefficient is the most frequently computed type of correlation. r sub xy equals begin numerator n sigma XY ? sigma X sigma Y end numerator over the square root of open square bracket n sigma X to the 2 power ? open parenthesis sigma X close parenthesis to the 2 power close square bracket open square bracket n sigma Y to the 2 power ? open parenthesis sigma Y close parenthesis to the 2 power close square bracket end radical where r sub xy equals ; the correlation coefficient between X and Y ; sigma equals ; the summation sign ; n equals ; the size of the sample ; X equals ; the individual’s score on the X variable ; Y equals ; the individual’s score on the Y variable ; XY equals ; the product of each X score times its corresponding Y score ; X to the 2 power equals ; the individual X score, squared ; Y to the 2 equals power ; the individual Y score, squared ; Test Yourself Let’s look at a simple example where the correlation coefficient is computed from data set C shown in Figure 9.1. The mean for variable X is 6.3, and the mean for variable Y is 4.6. Here is what the finished equation looks like: r sub xy equals ? .37 over 3 open square bracket 32.1 close square bracket open square bracket 62.4 close square bracket equals ? .82 Try it yourself and see if you can get the same result (rxy = ?.82). You can also use SPSS or Excel to get the answer. I must complete that test yourself and explain how they got that answer and the steps they took as well no plagiarism please thanks.