Then find the variance. The variance is calculated by subtracting the average from each score, then squaring, summing and finally dividing by the total. The specific calculation method is as follows:
(8 1-73.4)? +(98-73.4)? +(43-73.4)? +(75-73.4)? +(60-73.4)? +(55-73.4)? +(78-73.4)? +(84-73.4)? +(90-73.4)? +(70-73.4)? =2546
2546/ 10=254.6
So the sample variance of this test result is 254.6 (points).