A frequency table tells you how many items from a data set are in each category.

Within a frequency table:

- The mode is just the category with the most entries
- The range is just the difference between the highest and lowest categories
- The median is the category that contains the middle value of the second column
- To find the mean you add a third column that is the first two multiplied together like this:

The mean = total of third column / total of second column**Grouped Frequency Tables**

These are slightly harder. Each category has a class of data rather than just one value.

This means you can only guess the mean…to do so you need to make a 3rd column with the mid-interval values of each class and then a 4th column showing “frequency x mid-interval value”.To estimate the mean divide the total of the 4th column by the total of the 2nd.

Mean = (20 + 84 + 72 + 34) / (10 + 12 + 6 + 2) = 7**NOTE: If in the exam mode or mean come up in reference to a grouped frequency table, you will only be asked to find the modal class or median class, not the exact value.**

So for the table above the modal class would be “5 to 9”.