Correlation analysis types and methods ppt

Correlation

1. TYPES OF CORRELATION Positive and negative correlation Linear and non-linear correlation Simple, partial and multiple correlations Real and spurious correlations

2. METHODS OF STUDYING CORRELATION Scatter diagram Karl Pearson’s coefficient of correlation Rank correlation method

3. METHODS OF STUDYING CORRELATION Scatter diagram

4. METHODS OF STUDYING CORRELATION Scatter diagram Merits Very simple to study Easy to understand Extreme values don’t affect Demerits Idea about direction not amount/degree Large number of observations

5. METHODS OF STUDYING CORRELATION Karl Pearson’s coefficient of correlation

6. METHODS OF STUDYING CORRELATION Karl Pearson’s coefficient of correlation Properties Measure of closeness/relationship May be + ve or – ve -1 to +1 If r = 0, -1, +1 Independent of change of scale and origin GM of two regression coefficients Low (0 to 0.3), med (0.3 to 0.6), high (>0.6).

7. METHODS OF STUDYING CORRELATION Karl Pearson’s coefficient of correlation Merits Measure of degree/amount/magnitude of correlation Provides an idea about the direction of rel. Demerits Affected by extreme values Assumes linear relationship between two variables Time consuming Only for quantitative variables

8. METHODS OF STUDYING CORRELATION Spearman’s Rank correlation