So far we have learnt about three measures of central tendency: the mean, the median and the mode. These three measures all give us an approximation of where the centre is in a data set.

So when we are able to recognise the centre of data sets by finding the mean, median and mode, we can start to compare and make judgments about different data sets. We can say which one has the highest mode, the lowest median and so on.

Worked Examples

Question 1

For each of the following statements, decide whether they are true or false:

If two sets of data have the same median then the data sets must themselves be the same
True
A
False
B
If two sets of data have very different modes then the highest values cannot be the same
True
A
False
B

QUESTION 2

Select the data set from each of the options below that has:

The lowest mode.
$3,9,18,9,65,13$3,9,18,9,65,13
A
$5,12,16,16,86,3$5,12,16,16,86,3
B
The highest median?
$3,9,13,18$3,9,13,18
A
$9,16,16,65,86$9,16,16,65,86
B

QUESTION 3

Consider the two graphs. Select the dot plot that shows the lowest mode.

A

B

Outcomes

6.DP2.04

Demonstrate an understanding of mean (e.g., mean differs from median and mode because it is a value that “balances” a set of data – like the centre point or fulcrum in a lever), and use the mean to compare two sets of related data, with and without the use of technology

Recognising the centre of data