Graphs showing the relationship (or not) between two independent variables.
A line graph is the most useful type of graph for showing the relationship between two numerical variables. A bar graph can also be used since these two types of graphs are straightforward and simple.
The vast majority of all graphs do that.
Because cause and effect relationships in economics or in any other subject can be better explained with help of graphs. It also tells us what is the effect of one variable on other and how it responds to change in that variable. So instead of using words, graphs offer an easy and better way of showing relationships between two variables.
In my experience line graphs are powerful in science because of the relationship they show between two variables (showing how one variable changes as the other changes). But, more importantly in my view they allow the derivation of fomulas. For example, the formula v=u+at can be derived (notice the similarity to the equation of a line, y=mx+c) by drawing a graph showing speed against time.
Graphs showing the relationship (or not) between two independent variables.
A line graph is the most useful type of graph for showing the relationship between two numerical variables. A bar graph can also be used since these two types of graphs are straightforward and simple.
Graphs are a convenient way to display relationships between variables.
They illustrate the relationship between two (or more) variables.
Any graph.
The vast majority of all graphs do that.
a bar grapg can be used
Because cause and effect relationships in economics or in any other subject can be better explained with help of graphs. It also tells us what is the effect of one variable on other and how it responds to change in that variable. So instead of using words, graphs offer an easy and better way of showing relationships between two variables.
so you know the relationship between the 2 variables
In my experience line graphs are powerful in science because of the relationship they show between two variables (showing how one variable changes as the other changes). But, more importantly in my view they allow the derivation of fomulas. For example, the formula v=u+at can be derived (notice the similarity to the equation of a line, y=mx+c) by drawing a graph showing speed against time.
Pie graphs are good for showing a percent of something.
Some graphs do, but some don't. It depends upon the variables.