The mean of a numeric variable is calculated by adding together
the values of all observations in a dataset and then dividing by
the number of observations in the set. It is often referred to
as the average. Thus: Mean = sum of all the observations ÷
number of observations For example, find the mean of these
numbers 5, 3, 4, 5, 7, 6. |Mean ||= (5 + 3 + 4 + 5 + 7 + 6) ÷ 6|
|= 30 ÷ 6| Notice that the value of every member of the dataset
is used to calculate the mean. The median is the middle value of
a set of odd numbered data, or the mean of the middle two in an
even numbered set after the data have been placed in ascending
order. For example, dataset A contains 3, 7, 1, 9, 2, 5, 9.
Rearranged in ascending order it becomes: 1, 2, 3, 5, 7, 9, 9.
The middle number is 5 so, the median is 5. Dataset B contains
1, 3, 4, 5, 10, 12, 13, and also has a median of 5 although the
values of the data vary considerably. The position of the median
can also be found by using the formula (n + 1) ÷ 2 , where n is
the number of