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Unit 2 · Topic 02 · Data Analysis and Representation (Google Sheets)

Data and its uses

Hook

Every Friday the canteen ran out of samosas by 11 am.

Every Tuesday, forty-five cold ones went into the bin.

Nobody knew why. Everybody had a theory.

The Story

"Cook more," said Anaya. "Simple."

"More on which day?" asked Kabir.

Nobody could answer that, so Ms. Rao gave the class a job. For two weeks, one child would type the number of samosas sold into a Google Sheet each afternoon. Ten numbers. That was the whole task.

On day two Anaya announced the answer. "Tuesday is a big day. We sold 26!"

"Twenty-six is our smallest number so far," said Kabir. "And we only have two numbers."

Pixel's fan groaned. Even the old desktop knew that two numbers are not a pattern.

After two weeks the sheet showed 28, 26, 31, 29, 60 in week one, and 30, 27, 33, 28, 63 in week two. Friday stood out like a shout — roughly double every other day.

Kabir asked the canteen uncle why. Friday was games period, he said. Children came out hungry, with pocket money.

So the canteen changed one thing: 60 samosas on Friday, 30 on the other days. The old habit had been 45 every single day — far too few on Friday, far too many on Tuesday.

The next week six samosas went into the bin instead of forty-five. At ₹10 each, that is ₹390 saved in one week.

Ms. Rao made the class keep recording anyway. "How will you know it kept working?" she said.

In December the Friday numbers slipped. Games period had moved to Wednesday. The sheet noticed before anybody else did.

The canteen sales spreadsheet with columns A day, B week one and C week two, showing Friday roughly double every other day, and the waste before and after the change Sheet: Samosas sold each day A B C 1 2 3 4 5 6 Day Week 1 Week 2 Mon 28 30 Tue 26 27 Wed 31 33 Thu 29 28 Fri 60 63 about double BEFORE: cook 45 every day 45 wasted a week and Friday sold out by 11 am AFTER: 60 Friday, 30 other days 6 wasted a week 39 x ₹10 = ₹390 saved
Ten numbers, one pattern, ₹390 a week.

So What Just Happened?

Data is not collected for fun. It gets used, in five main ways.

To decide. Cook 60 or cook 30? The numbers chose, not the loudest opinion. To spot a pattern. One big Friday is luck; two Fridays at 60 and 63 is a pattern. To predict. A pattern lets you guess next Friday sensibly — about 60 again. To keep a record. The sheet remembers what really happened, long after memories blur. To check a change worked. Waste fell from 45 to 6, and the same record showed when it stopped working in December.

One warning lives inside all five: too little data looks exactly like an answer. Anaya's two numbers felt convincing, and were wrong.

The ten days of samosa data in the centre with five labelled uses around it: decide, spot a pattern, predict, keep a record and check a change worked THE DATA 10 days of sales 28 to 63 samosas 1. DECIDE Cook 60 Fri, 30 else 2. SPOT A PATTERN Friday about double 3. PREDICT Next Friday about 60 4. KEEP A RECORD What really happened 5. CHECK IT WORKED Waste 45 to 6 = ₹390 saved Warning: 2 numbers are not a pattern
Five jobs the same ten numbers did.

Remember This

  • Data is used to decide, spot patterns, predict, keep records, and check a change worked.
  • A pattern needs repeats. Two numbers are not a pattern.
  • Data beats opinion whenever the question has a number answer.
  • Keep collecting after the fix — that is how you notice when things change.
  • Data tells you what happened; people still have to find out why.
A cheat card listing the five uses of data as a checklist, with a do and do-not pair underneath CHEAT CARD - what is this data FOR? Decide 60 or 30? Spot pattern Friday is big Predict next Fri about 60 Keep record memory fades Check it worked 45 to 6 wasted DO collect for two full weeks Keep recording after the change DON'T decide on day two Guess the why from numbers alone
The five uses, and the two traps.

Try It Yourself

For one week, write down how many minutes you spend on homework each day. Seven numbers, nothing else.

On Sunday find your biggest day and your smallest day, then write one sentence predicting next Tuesday.

Next Tuesday, check it. Being wrong is useful data too.

Word Bank

Pattern
Something that repeats in the data, like Friday always being high.
Predict
To use a pattern to say what will probably happen next.
Record
Data kept safely so that you can look it up later.
Decision
A choice, better made from data than from a guess.
Waste
Things made but never used, like forty-five cold samosas.

Questions

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