
Find the Karl Pearson’s coefficient of correlation for the following data.

Important Points to Remember in Chapter -1 - Correlation Analysis from Tamil Nadu Board Statistics Standard 12 Solutions
1. Correlation and its types:
It is the study about finding the linear relationship between two variables
(i) Simple correlation:
(ii) Partial correlation
(iii) Multiple correlation.
2. Methods to find correlation:
(i) Scatter diagram
(ii) Karl Pearson's product moment correlation coefficient
(iii) Spearman's Rank correlation coefficient
(iv) Yule's coefficient of Association
3. Scatter diagram and types of correlation:
A scatter diagram is the simplest way of the diagrammatic representation of bivariate data.
(i) Positive correlation:
If the plotted points in the plane form a band and they show the rising trend from the lower left hand corner to the upper right hand corner.
(ii) Negative correlation:
If the plotted points in the plane form a band and they show the falling trend from the upper left hand corner to the lower right hand corner.
(iii) Uncorrelated:
If the plotted points spread over in the plane then the two variables are uncorrelated.
(iv) Perfect positive correlation:
If all the plotted points lie on a straight line from lower left hand corner to the upper right hand corner.
(v) Perfect negative correlation:
If all the plotted points lie on a straight line falling from upper left hand corner to lower right hand corner.
4. Karl Pearson's coefficient correlation:
5. Spurious correlation:
It means an association extracted from correlation coefficient that may not exist in reality.
6. Spearman’s rank correlation coefficient:
7. Spearman’s rank correlation coefficient for repeated ranks:
8. Yule's coefficient: