coefficient correlation

Coefficient Correlation

1. PRESENTATION ON COEFFICIENT CORRELATION By Irshad Narejo STATISTICSS FOR EDUCATION

2. Definition Correlation refers to a technique used to measure the relationship between two or more  variables. A   correlation coefficient   is a statistical measure of the degree to which changes to the value of one variable predict change to the value of another. A correlation can only indicate the presence or absence of a relationship, not the nature of the relationship.  Correlation is not causation . 

3. Correlation Coefficient Formula: Overview. Correlation coefficient formulas are used to find how strong a relationship is between data. The formulas return a value between -1 and 1, where: 1 indicates a strong positive relationship. -1 indicates a strong negative relationship. A result of zero indicates no relationship at all.

4. Positive Correlation Association between variables such that high scores on one variable tend to have high scores on the other variable A direct relation between the variables

5. Negative Correlation Association between variables such that high scores on one variable tend to have low scores on the other variable. An inverse relation between the variables

6. correlation coefficient formula One of the most commonly used formulas in statistic is Pearson’s  correlation coefficient formula .

7. SPSS vs Hand Calculation X Y XY X 2 Y 2 8 64 2 10 20 4 100 3 4 12 9 16 6 6 36 36 36 9 1 9 81 1 10 3 30 100 9 30 32 107 230 226 N ∑XY - ∑X ∑Y r = [ N ∑X 2 – (∑X) 2 ] [N ∑Y 2 – (∑Y) 2 ] (6 X 107) – 30 (32) [6 (230) – 30 2 ] [6 (226) – 32 2 ] r = -.797 (note cross products term in the numerator is negative) and R-square = .635

8. SPSS vs Hand Calculation

9. *Thank you *