The definition of the mean is that it is the most commonly used average. The following represents the mean:
Mean = sum of all values ÷ number of values
For example, the mean time for 5 cars accelerating 0 – 60 mph are as follows:
= (12.9 + 9.9 + 15.2 + 10.3 + 6.2) ÷ 5
= 54.5 ÷ 5
Outliers and their effect on the mean
Outliers is a data set which is significantly higher or lower than the other items which has the affect of reducing or increasing the mean materially. This therefore would cause a mean to be less accruate.