The error she made is Emi evaluated (46-78)² as - (32)² is wrong.
What is variance?
Variance is calculated as the average of squared differences of the data observations from the mean.
Given data: 87, 46, 90, 78, and 89.
Here, the first Emi find the difference of 89 - 78 correctly.
Now, Emi division is also correct.
Now, Emi evaluated (46 - 78)^2 as -(32)^2 is wrong.
(46-78)² = (-32)²
Here she used the negative sign outside.
Hence, Emi evaluated (46 - 78)^2 as -(32)^2 is wrong.
Learn more about this concept here:
https://brainly.com/question/9899363
#SPJ1