Unit 2 · Topic 10 · Data Analysis and Representation (Google Sheets)
Anaya's chart was beautiful. It was round, and it had four colours.
It also answered completely the wrong question.
Ms. Rao looked at it and asked, "So which day earned the most?"
Nobody could say.
The stall was over and the assembly display was due. Anaya had two little tables. One counted boxes sold — Ladoo 12, Barfi 9, Jalebi 15, Kaju Katli 4 — forty boxes altogether. The other held money by day: Monday ₹240, Tuesday ₹310, Wednesday ₹180, Thursday ₹420.
She selected the days, went to Insert ▸ Chart, and in the Chart editor picked a pie chart. Four slices appeared, glossy and colourful.
"Beautiful," said Kabir. "But which day was best?"
Anaya squinted. The Thursday slice looked biggest, probably. Monday and Tuesday looked… nearly the same. She could not tell whether Tuesday beat Monday by ten rupees or a hundred.
Pixel's fan gave its usual opinion.
"A pie is a good chart," said Ms. Rao. "It shows how one whole splits into parts. But your question is not about shares. Your question is 'which is bigger, and by how much?'"
She had Anaya open the Chart editor again and change the chart type to a column chart — bars standing side by side. Now it was obvious. Thursday towered over the rest. Tuesday's bar sat clearly above Monday's, and the gap measured seventy rupees against the scale.
"Now do the boxes," said Ms. Rao.
Anaya selected the sweets table, chose Insert ▸ Chart, and this time a pie was exactly right. Forty boxes made one whole stall, and each sweet was a slice of it. Jalebi filled well over a third. Kaju Katli was a thin wedge.
"So the pie isn't wrong," said Kabir. "It just answers a different question."
Anaya printed both.
A pie chart shows how one whole splits into parts. Every slice is a share of the same total, and all the slices add up to 100%. Forty boxes made one whole stall, so 15 jalebi boxes became a slice worth 37.5%.
A bar chart compares separate amounts side by side. Heights are easy to judge against a scale, so you can see not only which is biggest but by how much.
Both charts come from Insert ▸ Chart, and you pick the type in the Chart editor. Choose by your question. "What share of the whole?" is a pie. "Which is bigger, and by how much?" is a bar. Slices of nearly equal size are very hard to compare, and that is where a pie lets you down.
List how you spent one Sunday — sleeping, school work, playing, screen time, meals — in hours, adding up to 24. Insert a pie chart of that.
Now list four friends' cricket scores and insert a bar chart of those.
Say out loud which question each of your two charts answers.
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