Level 2 · Ages 8–11
Read it again any time, including while you work through the exercises.
You ask your friends for their favourite colour and you write everything down in the order they answer: blue, red, blue, green, blue... The result: a long, messy list where you cannot see anything! To see clearly, you need to organise this data.
Organising means grouping together things that belong together. You take each category (blue, red, green) and count how many times it appears in the list. That number is called the count, or frequency count, of the category.
To count without mistakes, there is a champion's trick: tally marks. For each answer, you draw a small stroke in the right category. At the end, you count the strokes. Even better: cross out each answer in the list as you go, so you never count anything twice and you never miss one.
Once the counts are done, you put them in a table: one column for the categories, one column for the counts. And there you go: the messy list has become clear information, ready to be read or drawn as a chart.
Sorting also means putting objects or numbers into groups following a rule: even or odd, smaller or bigger than 10, animals with fur or with feathers. You are going to practise all of this, like a true data detective!
Here are the favourite colours written in order: blue, red, blue, green, blue, red, red, blue. Build the table of counts.
bleu : 4
I cross out each blue in the list as I count it: one, two, three, four. The count for blue is 4.
rouge : 3
I do the same for red: three answers. The count for red is 3.
vert : 1
One green is left. I check my total: 4 + 3 + 1 = 8, the same as the number of answers in the list. Everything is counted!
Result: Table: blue 4, red 3, green 1 (total 8).