1. How do you know the highest and lowest values on the vertical axis of a cumulative frequency graph

The lowest value in a cumulative frequency graph is always 0. 
The highest value will be the sum of each frequency.

2. Can the mode be worked out from a frequency table of GROUPED data?

Yes, the group or class with the highest number is called the modal class or group.

3. How is the mode found in a frequency table?

The mode is the most frequent or popular value so the value with the highest frequency will be the mode.

4. Can the mean be worked out from a frequency table of GROUPED data?

Yes, the mid-point of each group or class is multiplied by its frequency.

5. How is the range worked out from a frequency table?

The range will be the last value in the table minus the first value in the table.