These are just used to represent grouped data. You take the mid-interval value of each class and draw a straight line between each of the points you plot.
So for this table:The graph would be this:Easy!
Two Way Tables
These show two types of info in the same table…and can help you to work out tricky questions.
Example: 150 men and 150 women were asked if they are left handed. 45 people altogether were left handed. 120 women were right handed. How many men were right handed?
First make a two way table like the example below with the info you have:Then you can work through the missing squares on the table by adding and subtracting: