Answer:
Option C.
Step-by-step explanation:
For a given set of N elements:
{x₁, x₂, ..., xₙ}
The mean is given by:
[tex]M = \frac{x_1 + x_2 + ... + x_n}{N}[/tex]
And the variance is given by:
[tex]v = \frac{(x_1 - M)^2 + (x_2 - M)^2 + ... + (x_n - M)^2}{N}[/tex]
Then for our set:
{70, 80 ,75, 75, 80}
We have 5 elements, then N = 5
The first thing we need to find is the mean.
[tex]M = \frac{70 + 80 + 75 + 75 + 80}{5} = 76[/tex]
Then the variance will be:
[tex]v = \frac{(70 - 76)^2 + (80 - 76)^2 + (75 - 76)^2 + (75 - 76)^2 + (80 - 76)^2}{5} = 14[/tex]
The correct option is C, 14.