Statistical Diagrams

Sorting data before displaying it

• Discrete data can be counted and takes only separate values, such as the number of pets or a shoe size
• Continuous data is measured and can take any value in a range, such as a height or a time
• Categorical data is not numerical at all, such as a colour or a favourite subject
• A tally chart records data as it is collected, in groups of five, and becomes a frequency table once the tallies are counted
• A two-way table cross-classifies by two characteristics at once, with the row and column totals as a built-in check
• The type of data decides which diagram is appropriate, which is why classifying comes first