Question

The city's PR manager claimed the mean score of all ninth graders in the city was 83 (because the average of 81, 96, and 72 is 83). Of course, that is incorrect. Write a sentence or two to explain why this approach is incorrect.

Answer 1

The city's PR manager was wrong because the mean score of all ninth graders in the city is 83.

Explanation:

The given observations are:

81, 96 and 72

The total number of observations = 3

We know that,

Mean =
`(Sum of all observations)/(Total number of observations)`

`=(81+96+72)/(3)`

`=(249)/(3)`

= 83

∴ The mean score of all ninth graders in the city = 83

The city's PR manager was wrong because the mean score of all ninth graders in the city is 83.