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Statistics

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A long list of readings is hard to remember. A table is easier to read.

A list becomes four classes, then four bars.

This is Chapter 13, Statistics, in your Class 10 book. You already know the mean, median and mode of a plain list. Here the data comes as a table of classes.

What you will learn

  • Classes. Group a list into classes and count each class.
  • The class mark. One number represents each class.
  • The mean. Three ways: direct, assumed mean, step deviation.
  • The median. Count up to half of n, the number of readings. Then use the formula.
  • The mode. Find the tallest class, then use the formula.
  • Choosing. Decide which average answers the question.
  • Missing numbers. One or two frequencies are hidden. Find them.
  • Gaps and running totals. Make classes touch. Read a "below" table.

Every table here is made up. The method stays the same for real data.

Jump to lesson

This track

  1. 0 Start here
  2. 1 From a list to classes
  3. 2 The class mark
  4. 3 The direct mean
  5. 4 The assumed mean
  6. 5 Step by step
  7. 6 Checkpoint: tables, marks and three means
  8. 7 Counting to the median
  9. 8 The modal class
  10. 9 Which average, when
  11. 10 Checkpoint: counting and choosing
  12. 11 One table, three averages
  13. 12 Find the missing frequency
  14. 13 Two missing frequencies
  15. 14 Close the gaps between classes
  16. 15 From a "below" table to classes
  17. 16 Checkpoint: missing numbers, gaps and running totals
  18. 17 The big picture
  19. 18 Track quiz

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