If a sample of 51 employees were taken from a population of 606 employees. s² could refer to the variance of how many employees salaries?
a. 606
b. both 51 and 606
c. neither 51 or 606
d. 51

In calculating for the variance, we use the actual sample size and not the population size. In this case since we are only using a sample size of 51 employees, then s^2 or sample variance refers to the variance of 51 employees.

Therefore the answer is letter D. 51

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15