Step 1: Find the mean (average) of the data set. Add all the numbers together: 5 + 7 + 8 + 9 + 10 = 39. Then divide by the number of values (5): 39 / 5 = 7.8.
Step 2: Calculate the variance. For each number in the data set, subtract the mean (7.8) and square the result: (5 - 7.8)², (7 - 7.8)², (8 - 7.8)², (9 - 7.8)², (10 - 7.8)².
