Emi computes the mean and variance for the population data set 87, 46, 90, 78, and 89. She finds the mean is 78. He steps for finding the variance are shown below. 2 (87-78)2+(46-78)+(90-78)+(78-78)+(89-78)2 5 (9)-(32) + (12)+(0)+(11) 5 81-1,024+144+0+121 5 -678 5 --135.6 What is the first error she made in computing the variance? Emi failed to find the difference of 89 - 78 correctly. Emi divided by N-1 instead of N.