Next, calculate the deviations from the mean:
Now, calculate the squared deviations:
Q: What is the difference between Sxx and Syy? A: Sxx and Syy are both sum of squares formulas, but Sxx represents the sum of squared deviations from the mean of x, while Syy represents the sum of squared deviations from the mean of y. Sxx Variance Formula
Finally, calculate Sxx:
| Student | Score | Deviation from mean | | --- | --- | --- | | 1 | 80 | 0 | | 2 | 70 | -10 | | 3 | 90 | 10 | | 4 | 85 | 5 | | 5 | 75 | -5 | Next, calculate the deviations from the mean: Now,
where E denotes the expected value, and μ represents the population mean.
By dividing Sxx by (n-1), we get the sample variance: By dividing Sxx by (n-1), we get the
Suppose we have a dataset of exam scores: