Write brief notes on the following …

A bar graph represents data using a series of bars across two axes. The x-axis (the horizontal) classifies the data by group, with one bar for each group. So for example, if you were displaying the number of beads of each color in a jar, the x-axis would have a section for each color, and each color would have its own bar. The y-axis (the vertical) shows the value for the category for each bar. In the bead example, this would be the number of beads. So the bar for green beads might extend up to five, for example, whereas the bar for red beads may extend up to only two. The y-axis can be many different values, though; for example, money, a growth rate, an average speed or even a percentage of the whole. Similarly, the x-axis values and bars could represent the same quantity at different points in time, and this capability shows a big difference between bar graphs and pie charts.

Pie charts are circular graphs that display percentages of a whole as if they were slices of a pie. This is very similar to bar graphs in that the individual slices of pie mean that the data has to have the potential to be categorized. The “slices” of the pie have sizes to indicate the proportion of the whole they represent (although a legend beside the chart usually shows the precise figures), but unlike bar graphs, pie charts can’t be used to explicitly show absolute number values for each group. The shape is the most obvious difference between pie charts and bar graphs, but the restriction to proportions with pie charts is the most important