Answer:
0.77
Step-by-step explanation:
What we must do is apply the formula they give us and then apply absolute value, add and find the mean of the result and that would be the variance, like this:
18.9 - 20 = -1.1 = 1.1
20.7 - 20 = 0.7 = 0.7
19.3 - 20 = -0.7 = 0.7
20.1 - 20 = 0.1 = 0.1
21.3 - 20 = 1.3 = 1.3
19.6 - 20 = -0.4 = 0.4
20.5 - 20 = 0.5 = 0.5
20.9 - 20 = 0.9 = 0.9
18.8 - 20 = -1.2 = 1.2
20.8 - 20 = 0.8 = 0.8
(1.1 + 0.7 + 0.7 + 0.1 + 1.3 + 0.4 + 0.5 + 0.9 + 1.2 + 0.8) / 10 = 0.77
That is, the variance is 0.77
