Collecting data
How to collect and record data
Data is information you collect to answer a question. When you plan carefully and record data neatly, it is easy to read and helps you make decisions.
Statistical questions and planning
A statistical question is one you answer by collecting data, such as 'How many star jumps can we do in one minute?'. Before you start, plan your investigation: ā¢ the people you will use ā¢ what you will ask them to do ā¢ the equipment you need (like a stopwatch) ā¢ how you will record the data.
Tally charts and frequency tables
A tally chart is a quick way to count. Each item is a mark, and every fifth mark is drawn across the group of four so fives are easy to count. The total for each row is its frequency ā how many times that value appears. For example, if six children wear size 34 shoes, the frequency of size 34 is 6.
Dot plots
A dot plot shows data with dots above a number line. ā¢ Draw and label an axis long enough for all the values. ā¢ Put one dot above a number for each time it appears. If 0 appears four times in the data, you draw four dots above the 0.
Reading the data
Once data is recorded you can answer questions about it: ā¢ the greatest and least values ā¢ the total by adding the numbers ā¢ how many are more or less than a certain value. Always label your chart so a reader knows what it shows.
Worked examples
Plan an investigation
- Question: How many star jumps can each friend do in one minute?
- Decide the people, the task, and that a stopwatch is needed.
- Choose to record the results in a table.
Answer: A clear plan lists the people, the task, the equipment and how to record.
Count with a tally / frequency
- Shoe sizes include 34 six times.
- Draw four marks then a fifth across them, then one more mark.
- The total (frequency) for size 34 is 6.
Answer: The frequency of size 34 is 6 children.
Read a dot plot of pets
- Data: 0, 1, 3, 1, 1, 0, 2, 4, 1, 2, 2, 0, 0.
- Count how many people have 0 pets by counting the 0s.
- There are four 0s.
Answer: 4 people have 0 pets.
Find the total of a set of results
- Star jumps: Ben 30, Cerys 24, David 27, Eli 32.
- Add the numbers together.
- 30 + 24 + 27 + 32 = 113.
Answer: The total is 113 star jumps.
Where you see this in real life
- Counting how many children wear each shoe size in a class.
- Recording how many pets each person has.
- Finding out which cake flavour people like best for a fair.
- Timing how many multiples of 4 you can write in two minutes.
Key words
- Data
- Information you collect to answer a question.
- Statistical question
- A question you answer by collecting and looking at data.
- Tally chart
- A chart that counts items using marks, with every fifth mark across a group of four.
- Frequency
- How many times a value appears in the data.
- Dot plot
- A chart that shows data with dots above a labelled number line.