Here are 10 values of a variable x. find the variance using the formula u=x-20

18.9

20.7

19.3

20.1

21.3

19.6

20.5

20.9

18.8

20.8

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