New Zealand
Level 6 - NCEA Level 1

# Recognising the centre of data

Lesson

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:

1. If two sets of data have the same median then the data sets must themselves be the same

True

A

False

B

True

A

False

B
2. If two sets of data have very different modes then the highest values cannot be the same

True

A

False

B

True

A

False

B

##### QUESTION 2

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

1. 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

$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
2. The highest median?

$3,9,13,18$3,9,13,18

A

$9,16,16,65,86$9,16,16,65,86

B

$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.

1.  ​
A
 ​
B
 ​
A
 ​
B

### Outcomes

#### S6-1

Plan and conduct investigations using the statistical enquiry cycle: A justifying the variables and measures used B managing sources of variation, including through the use of random sampling C identifying and communicating features in context (trends, relationships between variables, and differences within and between distributions), using multiple displays D making informal inferences about populations from sample data E justifying findings, using displays and measures.

#### 91035

Investigate a given multivariate data set using the statistical enquiry cycle