We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.

Therefore, our variance is 225.
Answer:
Step-by-step explanation:
You should know that quotient is the result of division.
n/2
Four less than that would be subtracting.
(n/2) - 4 = 9
All real numbers except -4 and 9.
The domain of an expression is the range of all values for which the expression is defined. Looking at the expression, it will legal everywhere except when a^2 - 5a - 36 is equal to 0. Since that's a quadratic equation, we can use the quadratic formula to find where its value is 0, giving -4 and 9.
Therefore the domain of the expression is, All real numbers except -4 and 9.