Summarising and graphing data

Question 1

Data summary - 4

Answer 1

• Can be graphical or numerical
• Choice of representation method depends on level of measurement
• Summarisation has to answer research question
• Typically we look for data distribution

Question 2

Graphical summarisation - 3

Answer 2

• Tables, graphs or other figures
• Scale can change the appearance of data
• When comparing data sets, it is best to use same scale

Question 3

Descriptive summarisation - 2

Answer 3

• Qualitative describe shape and dispersion/variation

- Quantitative, numerical summaries of location and variation

Question 4

Frequency distribution - 1

Answer 4

• Counts occurrences of category or number of values in interval
• Can be cumulative and relative

Question 5

Cumulative frequency - 1

Answer 5

• Indicates all occurrences which are less than the current value

Question 6

Relative frequency - 1

Answer 6

• Shows how big the count value is relative to the total number of counts

Question 7

Bar Charts - 2

Answer 7

• Can be used to represent Qualitative data against a value.
• Each category’s value is represented by its bar size

Question 8

Pareto bar charts - 2

Answer 8

• Orders bar charts with respect to frequency.

- Can only be applied to data of nominal level of measurement

Question 9

Pie chart - 2

Answer 9

• Size of each piece is determined by relative frequency of category.
• Mainly used for qualitative data

Question 10

Histogram - 2

Answer 10

• Plots frequency against intervals.
• Frequency of each interval is determined by the bar (bin) size.
• Scale and interval size can change aspect of the histogram

Question 11

Difference Histogram / Bar Chart - 2

Answer 11

• Histograms bars are in natural order and always adjacent, bar charts are separated
• Histograms are used for quantitative data, bar chart for qualitative

Question 12

Time series plot - 1

Answer 12

• Graphical representation of a quantity which varies over time