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