Why does the formula for calculating the sample variance, s squared equals startfraction summation from nothing to nothing left parenthesis x minus x overbar right parenthesis squared over n minus 1 endfraction s2= ∑x−x2 n−1 , involve squaring the difference between each value and the mean?

Simplify (1/2)4th power a. (1/16) b.(1/8) c.(1/4)

Astudent found the solution below for the given inequality. |x-9|< -4 x-9> 4 and x-9< -4 x> 13 and x< 5 which of the following explains whether the student is correct? -the student is completely correct because the student correctly wrote and solved the compound inequality. -the student is partially correct because only one part of the compound inequality is written correctly. -the student is partially correct because the student should have written the statements using “or” instead of “and.” -the student is completely incorrect because there is no solution to this inequality.

Which angle of rotation is an angle of rotational symmetry for all figures?