Learn about defining the correlation coefficient and understanding what "r" says about the relationship between the two variables.
- In our previous video,…we calculated R squared.…For our basketball player data set,…R squared was zero point nine four five and note,…the r in R squared is a capital r.…In our world of regression though,…we also have a lowercase r.…This lowercase r is our correlation coefficient…and there's a relationship between R squared and r.…R, the correlation coefficient,…is equal to…the square root of R squared…and the sign of our correlation coefficient…is the same as the slope of our regression line.…
In the case of our basketball player data set,…the regression line had a slope…of positive eight point eight three.…So if we want to calculate r,…the correlation coefficient,…first, we know the sign would be positive.…Second, we take the square root of R squared,…zero point nine four five.…That means that r, the correlation coefficient,…is positive…zero point nine seven two…and what does that mean?…Well, let's look at this graphically.…
This is what a r of positive one would look like.…And here is the data for a r of negative one.…
- Working with small sample sizes
- Using t-statistic vs. z-statistic
- Calculating confidence intervals with t-scores
- Comparing two populations (proportions)
- Comparing two population means
- Chi-square testing
- ANOVA testing
- Regression testing
Skill Level Advanced
1. The Statistics Series: A Look Back and Forward
2. Small Sample Sizes
T-statistic vs. z-statistic3m 44s
3. Comparing Two Populations (Proportions)
4. Comparing Two Populations (Means)
6. ANOVA: Analysis of Variance
7. Introduction to Regression
Next steps1m 40s
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