Data types and representationData types and representation

Two types of data:

Observations are a finite, countable,

number of values

Observations are a finite, countable,

number of values

Discrete

Observations can take on any

number of the countless number

of values in

an interval

Continuous

eg. Number of “sixes” after 3 throws of the dice

eg. The average IQ of ten random Heads of Department

Data types and representationData types and representation

Types of measurementsNominal

Objects are named and assigned to classes

eg. male or female

Ordinal

Objects are either greater, or smaller than, a comparative object

eg. finishing positions in a race

Ratio level

Basic standard interval exists + meaningful zero

eg. mass

Interval level

Basic standard interval is introduced, but no true zero

eg. temperature in celsius

Data types and representationData types and representation

Summarising

discrete data:

Name Eye ColourJanice brown

Tom blue

Danielle green

Ian brown

Eduardo brown

Emily brown

Anja blue

Cara brown

Adrian brown

Eric blue

Sarah brown

David brown

Data types and representationData types and representation

Summarising

discrete data:Frequency tables

Eye Colour Frequency

Brown

Blue

Green

33

14

3

Data types and representationData types and representation

Summarising

discrete data:

Eye Colour FrequencyRelative Frequency

Brown

Blue

Green

33

14

3

66%

28%

6%

Frequency tables

Data types and representationData types and representation

Summarising

discrete data:

Frequency bar graph

Data types and representationData types and representation

Summarising

discrete data:

Relative frequency bar

graph

Data types and representationData types and representation

Summarising

continuous data:

Name

Hours of

Sleep / NightJanice 6

Tom 7.5

Danielle 10.5

Ian 9

Eduardo 7

Emily 6

Anja 8

Cara 5

Adrian 8.5

Eric 6.5

Sarah 7.5

David 4

Data types and representationData types and representation

Hours of Sleep Frequency

3 - 4 hrs

4 - 5 hrs

5 - 6 hrs

6 - 7 hrs

7 - 8 hrs

8 - 9 hrs

9 - 10 hrs

10 - 11 hrs

1

3

6

14

16

5

3

2

Summarising

continuous data:

Frequency tables

Data types and representationData types and representation

Summarising

continuous data:Frequency bar graph

(Histogram)

0

5

10

15

20

3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5

Nightly hours of sleep

Fre

qu

ency

Data types and representationData types and representation

Summarising

continuous data:

Relative frequency bar chart

0

10

20

30

40

3.5 4.5 5.5 6.5 7.5 8.5 9.5 10.5

Nightly hours of sleep

Fre

qu

ency

(%

)

Data types and representationData types and representation

Summarising

continuous data:

Line graph

Data types and representationData types and representation

Summarising

continuous data:

Scatter graph