information : representing data
 

bar/block graph

 

 

 

Bar/block graph

 

block graph

 

Not to be confused with a histogram, a bar chart/graph has columns of equal width, with height representing some variable, usually a number(eg frequency, % money).

The base of each column can represent anything (eg a car type, a person's name, a company).

Unlike a histogram, in a bar graph the columns need not be adjacent to eachother .

 

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Pie Chart

 

pie chart

 

car make

% imports into country X

Ford

20

Ferrari

12

Renault

26

Honda

35

Volvo

7

 

The angle in degrees for each car make is given by:

'% import' x 360
100

 

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Scatter diagrams/graphs

 

scatter diagrams

 

When two sets of data are plotted against eachother, a scatter of points is produced.

Correlation is the relationship between one set of data and the other.

An exact correlation would be '1' (a straight line graph with all the points on the line), while a zero correlation is '0'.

The first graph would have a correlation between 0 and 1.

The second graph would have a correlation between 0 and -1.

The third graph would have a correlation close to zero.

 

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Stem & Leaf table

Stem & leaf tables are similar to bar charts but differ in two distinct ways:

the pattern is horizontal not vertical

the display is made from numbers, not block colour

The data is placed in number order in groups of tens. It is then displayed horizontally for each tens grouping, starting with 0-9 at the top.

stem and leaf #1

The numbers displayed are:

2

11 13 15

20 24 24 26 29

34 36 38 38 39 39 39

47 48 49 49 49

51 51 53 54 58 59

60 61 61 62

73 74 75

82

 

 

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