Summarising data

What types of data can be presented in various ways?

• Qualitative and quantitative data can be presented using tables, graphs, or verbal summaries

What is qualitative data?

• non-numerical data collected from methods like interviews, observations, or open-ended surveys

What is quantitative data?

• numerical data that can be analysed statistically and summarised using tables and graphs

Why are tables useful in summarising quantitative data?

• they clearly present data and show patterns or raw scores before analysis

What are descriptive statistics?

• summaries such as the mean, range, and standard deviation used to describe data sets

What kind of data is shown in bar charts?

• non continuous (categorical) data

Why must the bars in a bar chart not touch each other?

• because the data is discrete (separate categories) and not continuous

What kind of data is shown in line graphs?

• continuous data, where values are measured along a scale

What are line graphs good for?

• showing plotted data over time or comparing multiple data sets on the same axes

What kind of data is shown in histograms?

• continuous data, grouped into intervals (like time taken, height, or age)

How do histograms differ from bar charts?

• histogram bars touch (continuous data); bar chart bars don't (discrete data)

What does the height of a column in a histogram represent?

• the frequency (number of values) in that interval

What kind of data is shown in scattergrams?

• two continuous variables plotted to show a possible correlation

What can scattergrams show?

• whether two variables are related, positively, negatively, or not at all

What is plotted on a scattergram?

• one variable on the x-axis, the other on the y-axis

Why must you not draw a line in scattergrams?

• you should draw a line of best fit only if a clear trend is visible to summarise the relationship

What is raw data?

• unprocessed scores collected before any statistical analysis

How do you calculate a percentage from a table?

• divide the part by the whole and multiply by 100 (e.g. 36/60 × 100)

What should you always include when plotting a graph?

• labels for axes (including units), title, and accurate plotting