Collect and tally

The idea

You can collect simple data by asking or watching, then tally the answers into a table of counts.

How would you keep count?

Mr. Fernandes asks 20 children, one by one, which sweet they want at the class party. How would you keep count?

• Remember each answer in my head
• Write every answer in one long list, then count later
• Give each sweet its own row and add a mark for each vote

Tally the votes

Twenty children have voted for the sweet they want at the class party. Add a mark for every vote. Watch what happens on the fifth mark.

A pile of answers becomes a table

Asking people, as Mr. Fernandes did, is a survey. Watching and counting is observation, and using a ruler is measurement.

Each vote went into one row, and the fifth mark crossed the other four. The last column shows each sweet's count. Together they make 20, the number of children. If they did not, a vote was missed or counted twice.

A tally adds one mark in the row for each answer, so many answers become one small table of counts.

The count in each row is its frequency. Data in neat rows and columns is called structured data.

Notes

A tally adds one mark in the row for each answer, so many answers become one small table of counts.

Check that the counts add up to the total. Collect only what your question needs, never more.

Check yourself

Gurpreet's class tallied the sweet for their Baisakhi party. How many children chose Pinni?

Answer: 13 children

Two bundles of five make 10. Three loose marks make 13.

Zoya's class has 32 children, and each voted once for a snack. The tally shows Samosa 11, Idli 9 and Sandwich 7. How many voted for Biscuits?

Answer: 5 children

11 + 9 + 7 = 27, and 32 − 27 = 5. A tally should always add up to the number of children.

Asha wants to know which subject each classmate likes best. Which way of collecting data fits best?

Meera runs a survey on favourite snacks. Her sheet only needs counts. What should she write down for each vote?

• A survey: ask each classmate, then tally — correct. Yes. A favourite is something only the person can tell you, so you ask. Watching can show what people do, and measuring suits things like height.
• Observation: watch what they do in class. Watching shows what people do, not what they like best. Some things you can only find out by asking.
• Measurement: use a ruler or a scale. Measuring uses an instrument for things like height or weight. A ruler cannot read a favourite.
• The child's name, class and phone number. None of these help to count snacks. Extra personal details can be misused, so do not collect them.
• The child's name and a tally mark. A name is not needed to count votes, and it shows who chose what. Collect only what your question needs.
• Only a tally mark in the snack's row — correct. Yes. Counting needs only the marks. When you collect less, everyone's choice stays more private.