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Grouping data into classes

This page was translated from German with AI. It has not been checked by a native speaker. Original page in German

When there are many different values, you group data into classes (die Klassen), for example „\(145\) to under \(155\) cm“.
📄 Open worksheet (PDF, German)

The video

In the video we sort \(20\) body heights into classes of width \(10\) cm and draw the diagram.

Subtitles are available in ten languages. Choose them at the bottom right of the video.

Contents of the video

  1. 0:00 Introduction
  2. 0:15 Making classes
  3. 0:30 Counting frequencies
  4. 0:46 The diagram
  5. 1:07 Careful, mistake!
  6. 1:26 Try it yourself

The most important points

Classes

Divide the values into classes of equal width: \(135\) to under \(145\), \(145\) to under \(155\), … Each value belongs to exactly one class.

Four classes, each 10 cm wide.
Four classes, each \(10\) cm wide.

With a tally chart (die Strichliste) you count how many values are in each class: \(3\), \(9\), \(7\), \(1\).

The tally chart for the heights.
The tally chart for the heights.

In the diagram the bars stand next to each other without gaps.

Bar chart of the classes.
Bar chart of the classes.

Careful: \(145\) belongs only to the class „\(145\) to under \(155\)“, not also to the class before.

The worksheet

Here you can see the worksheet for the video (in German). First it explains everything again, then there are practice tasks at three levels. You can also open it as a PDF and print it.

📄 Open worksheet (PDF, German)

The worksheet – Page 1
Page 1/4
The worksheet – Page 2
Page 2/4
The worksheet – Page 3
Page 3/4
Show the worksheet solutions
The worksheet – Page 4
Page 4/4

Try it yourself

Task

Waiting times in minutes: \(3, 7, 12, 5, 18, 9, 14, 2, 11, 6\). Classes: \(0\) to under \(5\), \(5\) to under \(10\), \(10\) to under \(15\), \(15\) to under \(20\). How many values are in each class?

Show solution

\(2\), \(4\), \(3\), \(1\).

Keep learning with a language model

Du bist meine Mathe-Lehrkraft. Ich lerne Deutsch als Zweitsprache. Unser Thema: Klasseneinteilung (Daten in Klassen gleicher Breite, Strichliste, Säulendiagramm). Stelle mir nacheinander fünf kurze Aufgaben. Warte immer auf meine Antwort. Sag mir dann, ob sie richtig ist, und erkläre kurz, warum. Benutze einfache deutsche Sätze.

How this was made: The idea, structure and examples of the series are mine. I made them with the help of AI: a language model (LLM) built the slides of the video following my instructions. The voice was generated with Qwen3-TTS, modelled on my own voice.

The subtitles, the translations, the worksheet and this page were also made with the help of AI. The translations have not been checked by native speakers.

The videos, worksheets, texts and prompts in this series are licensed under CC BY 4.0: you may use, change and share them if you name the source.