Graphical Representation

Question 1

What charts are used for qualitative data?

Answer 1

• Bar chart
• Pie chart

Question 2

What diagrams are used for quantitative data?

Answer 2

• Histogram
• Scatter diagram
• Time series plot
• Stem and leaf diagram

Question 3

What are the 3 ways of presenting statistics?

Answer 3

1. Words
2. Tables
3. Graphs

Question 4

What is the advantage of using words as a method of presenting statistics?

Answer 4

Translates big numbers into things people can understand

Question 5

What is the advantage of using tables as a method to present statistics?

Answer 5

Easy to understand the numbers that are sitting underneath what you’re saying

Question 6

What are the advantage of using graphs as a method to present statistics?

Answer 6

Can present large amounts of data

Shows patterns and relationships

Question 7

What things should you consider when choosing graphs?

Answer 7

• What type of data you have
• What is the data relationship you’re trying to show
• Who are your audience

Question 8

Why should you avoid 3D graphs?

Answer 8

3D diagrams can give a false interpretation of data being presented because it can make it difficult for the data values to be read accuratley.

It can also make segments of the bar chart look bigger than they are in proportion to other segments making it difficult to compare segments

Question 9

What number should a bar chart always start at and why?

Answer 9

0!

Provides an accurate picture of the data that it is representing

Question 10

What data type are bar charts used for?

Answer 10

Qualitative data

Question 11

On a bar chart, what are the labels on the axis’?

Answer 11

Catagories and frequency

Question 12

In a bar chart, what is the frequency of a catagory represented by?

Answer 12

The length/height of the corresponding bar

Question 13

It doesn’t matter if the bars in a bar chart are equal in width and separated by equal spacing.

True or False?

Answer 13

False!

The bars in the chart should be the same width and separated by equal spacing

Question 14

Describe a grouped bar chart

Answer 14

A seperate bar represents each sub-catagory of data and sub-catagory bars are then grouped together for each category

Question 15

Describe a pareto chart

Answer 15

A vertical bar chart that displays the bars in rank order of occurance from left to right

Helps identify the most important factors

Question 16

Describe a stacked bar chart

Answer 16

The bars representing the sub-catagories are placed on top of each other to make a single bar for each category

Question 17

What data types are pie charts used for?

Answer 17

Qualitative data

Question 18

What does each segment on a pie chart represent?

Answer 18

A category as a proportion of the whole data set

Question 19

What is the area of a segment of a pie chart proportional to?

Answer 19

The frequency of its corresponding catagory

Question 20

How is the angle in each segment of a pie chart calculated?

Answer 20

Relative frequency =

Category frequency/total frequency

Relative frequency X 360

Question 21

When is a pie chart less useful?

Answer 21

When there are many different catagories because the circle becomes cluttered with small segments

Question 22

What are the main advantages of using pie charts?

Answer 22

They are easy to construct and simple to understand.

They are visually appealing and therefore attract the attention of the audience

Question 23

What are the main disadvantages of using pie charts?

Answer 23

They cannot be easily be used to compare proportions of the same catagory in different data sets.

Making a visual comparison of the relative size of segments within a pie chart can also be difficult if perecentage values are not shown.

Question 24

What data types are histograms used for?

Answer 24

Quantitative data that has been organised into groups or classes

Question 25

What does the vertical axis of a histogram represent?

Answer 25

The frequency of the classes

Question 26

How is the frequency of the class represented if there are unequal class sizes in a historgam?

Answer 26

When using unequal class sizes, the frequency of the class will be represented by the **area** of the corresponding bar

Question 27

How is frequency represented in a histogram if the classes are the same width?

Answer 27

For classes of the same width, the height of each bar will represent the frequency of the class

Question 28

How are the bars drawn differently in a histogram compared to a bar chart?

Answer 28

In a histogram, the bars are drawn next to each other without gaps and the width of bars have specific meaning. Whereas in a bar chart the bars have to be equally spaced apart and all the bars have to be the same width.

Question 29

What does the horizontal axis of a histogram represent?

Answer 29

The class intervals

Question 30

What is a scatter diagram?

Answer 30

A graph used to display the value of two quantitative variables so we can observe any potential relationship between them

Question 31

What does each point on a scatter diagram represent?

Answer 31

A pair of data values for an individual entity

Question 32

When can a multiple scatter diagram be used?

Answer 32

To compare two different data sets on the same graph

Question 33

What is a scatter diargam particularly useful for?

Answer 33

Showing whether the data sets contain any extreme values

Question 34

What data does a stem & leaf diagram represent?

Answer 34

Quantitative

Question 35

What are the advantages of using a stem & leaf diagram be used?

Answer 35

It is good to observe patterns and highlight interesting features. Each individual data value is retained.

Question 36

What are the disadvantages of using a stem and leaf diagram?

Answer 36

It is a time consuming process when there are large data sets.