Working with data

Q: What do you call the value that turns up most often?

The mode — It is the mode. You use it when you want to know things like which size sells best.

Q: When there is one extremely large value, which one is closer to the real picture?

The median — The median is barely pulled around by extreme values, so it stays closer to the real picture.

Q: Which graph is best for showing shares of a whole?

Pie chart — A pie chart treats the whole as 100%, which makes it good for showing shares.

Q: Two shops have the same average. What do you look at to see the difference?

The spread — Even with the same average, a different spread means you have to prepare differently.

Q: Which is the right order for working with data?

Collect → organize → decide → check — Collect, organize, decide, check. You keep going round those four.

Where this is used

You collect numbers, tidy them up with means, medians and graphs, and then decide what to actually do about them. That is what working with data means. AI is built on the same foundation. This unit leads straight into statistics in middle and high school, and data science at university.

Key points

Summary values: mean, median and mode

A single value that stands in for a whole pile of numbers is called a summary value. The mean evens everything out, the median is the value in the middle, and the mode is the value that turns up most often. Which one you use depends on what you want to know.

Customers in a day (14 days, sorted into groups)

One day had 1000 people. The mean gets pulled up by it.

Look at the spread as well

Two shops can have the same average and still need completely different preparation: one is about the same every day, the other swings wildly from day to day. So never stop at "where is the middle?" — always ask "how spread out is it?" too.

Put percentages and graphs together

Use a pie chart for "what share of the whole is it?", and a line graph for "how did it change over time?". Choosing the graph that fits your purpose is what decides whether people understand you. Pie for shares, line for change, bars for comparing.

Ages of the customers who came to the shop

All the way from data to a decision

"People in their 20s are the biggest group, at 28%" → "put products for that age group by the entrance" → "count again in a month". Collect, organize, decide, check. Going round those four steps is what working with data is. In a job that uses AI, the order is exactly the same.

Check yourself 5questions

Tap an option to check

Q1 What do you call the value that turns up most often?

Q2 When there is one extremely large value, which one is closer to the real picture?

Q3 Which graph is best for showing shares of a whole?

Q4 Two shops have the same average. What do you look at to see the difference?

Q5 Which is the right order for working with data?

Jobs that use this

Every job uses this. The ones below are just where it shows up most.

Data scientist $130k

Product planner $72k

School or local government planner $55k

Data scientist$130k

Organizes the data a company has collected and proposes what it should do next. Long before building an AI model, they do a great deal of exactly what you did in this unit.

Maths used: MeansMediansPercentagesStatistics

Product planner$72k

Decides what product to make next, using surveys and sales data. The people who get their plans approved are the ones who can explain them with numbers instead of a hunch.

Maths used: MeansPercentagesGraphs

School or local government planner$55k

Pulls survey results together and decides on events and rules. They are answerable for which summary value they choose — and for whether it quietly throws away the minority's view.

Maths used: MeansMediansPercentages

Where this is used

Key points

Check yourself 5questions

Jobs that use this

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