Question

Calculating the degrees of freedom, the sample variance, and the estimated standard error for evaluations.

Answer 1

Answer:

The variance is  $\sigma ^2 =25$

Step-by-step explanation:

From the question we are told that

    The sample size is  n =  21

     The sum of squares is $SS = 500$

Generally the variance is mathematically represented as

           $\sigma ^2 = \frac{SS}{n- 1}$

substituting values

          $\sigma ^2 = \frac{ 500}{21- 1}$

          $\sigma ^2 =25$