Asking Questions and Collecting Data

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What this lesson covers

  • Data is information we collect to answer a question.
  • Category data is words, like colours or ways to get to school.
  • Number data is a count or a measure, like teeth lost or height in cm.
  • Sorting the answers makes them easy to count.
Key idea

Start with a question

  • An investigative question asks what we want to find out about a group.
  • How do the students in our class get to school?
  • How many teeth have the students in our class lost?
Key idea

Two kinds of data

  • Category data answers with words.
  • Number data answers with a number that is a count or a measure.
QuestionAnswers look likeKind of data
What is your favourite fruit?apple, banana, kiwifruitcategory
How do you get to school?walk, car, bus, bikecategory
How many teeth have you lost?0, 2, 5number (a count)
How tall are you in cm?118, 125, 131number (a measure)
Key idea

Try it: category or number?

Worked example

Sorting category data

  • Ask 20 students in Room 5: How do you get to school?
  • Write down every answer, then sort them into groups and count each group.
  • Check: 8 + 6 + 4 + 2 = 20 answers.
Way to schoolStudents
Walk8
Car6
Bus4
Bike2
Key idea

Try it: turn the counts into a graph

Worked example

Collecting number data

  • Question: How many teeth have the students in our group lost?
  • Answers from 12 students: 0, 2, 1, 3, 2, 0, 4, 2, 1, 2, 3, 2.
  • Every answer is a whole number, because it is a count.
  • Sort the answers by number and count each one.
Teeth lostStudents
02
12
25
32
41
Key idea

Good questions

  • A good question says who you are asking: the students in our class.
  • The answer should be easy to give: a word, or a whole number.
  • "Do you like apples?" only gets yes or no. "What is your favourite fruit?" tells you more.

Common mistakes

  • Favourite colour is number data.
    Colours are words, so favourite colour is category data.
  • Number of pets is category data because pets are animals.
    The answer is a count, like 0, 1 or 3, so it is number data.
  • Keep the answers in your head and count them later.
    Write every answer down, then sort and count them.
  • Leave out the students who lost 0 teeth.
    0 is an answer too. Count how many students lost 0 teeth.

Your turn

1

Which question gives number data?

2

Which question gives category data?

3

In the teeth table, how many students lost 2 teeth?

4

In the teeth table, how many students lost 3 or more teeth?

5

Eight students say how many pets they have: 1, 0, 2, 1, 1, 3, 0, 1. How many students have 1 pet?

Show answer

1. How many cousins do you have? 2. How do you get to school? 3. 5 4. 3 (2 students lost 3 teeth and 1 lost 4) 5. 4

Summary

What to take away

  • Start with a question about a group.
  • Category data is words. Number data is counts or measures.
  • Write every answer down, then sort and count.
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