All year we have posed questions and counted answers. Today we go the whole way, from the first question to the last sentence.

A fair survey starts with a fixed-answer question: one clear ask, and a short list of answers that every pupil can pick from. Every pupil must fit in exactly one answer, or the count is not fair.

Before any hands go up, check the list: is each answer clear, and does every pupil fit exactly one? That is how we pose a fixed-answer data question.

A data detective works through five steps in order:

• Pose a clear question.
• Collect fairly with a tally.
• Turn the tally into a frequency table. The frequency just means how many times that answer came up — the one number for each row.
• Display it as a bar chart.
• Write a conclusion.

Here is how a finished cycle works. If Walk has twelve tally marks, its frequency is 12. That 12 sets how high Walk's bar goes: twelve marks, twelve high. Every bar is set the same way, count the marks, and the frequency is the height.

Now we collect our own. Today we run the survey: What is your favourite break-time game? We agree on four answers first, then each of you calls yours out and a pupil at the board adds a tally mark to the right row.