1. What is the difference between a histogram and a bar (column) graph?

Histograms are used for continuous data such as frequencies of people of a range of heights or weights.

Bar graphs are used for discrete data such as the frequencies of the number of cars of a certain colour.

2. Can a pie graph be used for all types of data?

No. Pie graphs or charts are most suitable to data where proportions or percentages of a total amount are available .

3. How can the pictures in pictographs be turned into data?

Each picture represents a certain number of items. Thre may be half a picture which would represent 0.5 x number of items per picture.