Answer:
Variance = 0.16 and Standard deviation = 0.4.
Explanation:
I am assuming you want the population variance and standard deviation.
Mean = (16+5) / 5 = 21 / 5 = 4.2.
Subtracting the mean from the values we have
4 - 4.2 = -0.2 (4 of these)
5 - 4.2 = 0.8 .
The variance is the sum of the squares of these differences / the mean :
The variance = (4 * (-0.2)^2 + 0.8^2) / 5
= 0.8 / 5
= 0.16.
Standard deviation = sqrt 0.16 = 0.4.