Data & Big Data: fun facts and quiz

Data is recorded information: numbers, words, photos, clicks and sensor readings. On its own it’s raw; analysed, it becomes useful knowledge.

Key fact
“Data” is plural; one piece is a datum.

Data is measured in bytes. A kilobyte is about a thousand bytes, a megabyte a million, a gigabyte a billion, and a terabyte a trillion.

Key fact
A typical phone photo is a few megabytes.

Big data means datasets so huge and fast-moving that ordinary tools can’t handle them, like every search or card payment in a country.

Key fact
The world now creates well over 100 zettabytes of data a year.

Charts turn data into pictures. Bar charts compare amounts, line charts show change over time, and pie charts show parts of a whole.

Key fact
An axis that doesn’t start at zero can exaggerate differences.

Data can mislead through tiny samples, cherry-picked numbers or tricky charts. Asking “compared to what?” helps you spot it.

Key fact
A 100% rise from 1 to 2 is still tiny.

Data scientists clean data, look for patterns and build models to answer questions, like which treatment works best or when trains will be busiest.

Key fact
Cleaning messy data often takes most of the time.

Open data is shared freely for anyone to use, like weather records, maps and public transport times. Apps and researchers build on it.

Key fact
Many transport apps use cities’ open timetable data.