Emi computes the mean and variance for the population data set 87, 46, 90, 78, and 89. She finds the mean is 78. Emi's Work sigma squared is equal to the fraction with numerator open paren 87 minus 78 close paren squared plus open paren 46 minus 78 close paren squared plus open paren 90 minus 78 close paren squared plus open paren 78 minus 78 close paren squared plus open paren 89 minus 78 close paren squared and denominator 5 is equal to the fraction with numerator 9 squared minus 32 squared plus 12 squared plus 0 squared plus 11 squared and denominator 5 is equal to the fraction with numerator 81 minus 1 comma 024 plus 144 plus 0 plus 121 and denominator 5 =(−678)/(5) is equal to negative 135 point 6 What is the first error she made in computing the variance?