What is the variance? A teacher recorded all of his students’ grades on the final exam as:

62, 77, 78, 80, 82, 82, 83, 84, 85, 87, 89, 95

Consider the formulas:

A: s squared = StartFraction (x 1 minus x overbar) squared + (x 2 minus x overbar) squared + ellipsis + (x n minus x overbar) squared Over n minus 1. B: s = StartRoot StartFraction (x 1 minus x overbar) squared + (x 2 minus x overbar) squared + ellipsis + (x n minus x overbar) squared Over n minus 1 EndFraction EndRoot. C: Sigma squared = StartFraction (x 1 minus mu) Squared + (x 2 minus mu) squared + ellipsis + (x N minus mu) squared Over N EndFraction. D: Sigma = StartRoot StartFraction (x 1 minus mu) Squared + (x 2 minus mu) squared + ellipsis + (x N minus mu) squared Over N EndFraction EndRoot