Collecting and Organising Data

The data cycle has four stages: pose a question, collect data, organise it, then analyse and report. This lesson covers collecting and organising.

Data comes in two kinds:

• Categorical data sorts into groups — favourite subject, mode of transport, eye colour.
• Numerical data is counted or measured — height, test score, number of learners.

To organise raw data we use a tally and a frequency table. Each stroke is one count; a group of five is written as a gate (four strokes crossed by a fifth). A frequency table lists each category next to how many times it occurred.

Exam checkpoint

A fair data investigation begins with a clear question, a sensible sample and a method that records every response in the same way. Decide whether data are categories (favourite fruit) or numerical values (minutes travelled). Make a tally table before counting totals.

Short worked example. Question: ‘How does each learner travel to school?’ Tally walk, taxi, bus and car. Then turn the tally marks into frequencies so a graph can be drawn.