When do you use which type of graph?

Question

I'm going to be doing some survey data input into a database and I was wondering what type of graph to use. This got me thinking about what graph type is used for which? What are bar graphs for? pie graphs? histograms? etc. Could someone tell me what each type of graph does and what it's used for please? Thanks in advance!

What's the difference between a bar graph and histogram? I can't tell the difference (at least not visually).

What would you guys recommend I use for a survey that asks a few questions on range of agree/disagree, age, and gender?

Answer 1

bar graphs are best for comparing data

pie graphs are great if you want to show the porportions of your data

histograms are used to compare data over certain intervals

you could use a double bar graph to compare two different variable in a certain category (ex: # boys & girls in volleyball, basketball, and swimming)

or would could use a line graph to show change of time (you can double these up when comparing (ex: which paper towel lasts the longest? bounty or viva?)

Answer 2

Pie graphs are useful when you have a certain fraction of 100% with certain characteristics. For example, if you asked people to pick between three movies, and 25% chose the first movie, 35% chose the second movie, and 40% chose the third movie, you could represent this with a pie graph with three color-coded slices of different sizes. The three slices fit together to form an entire circle, representing 100%.

Histograms are one type of bar graph. They are useful when you want to put a spectrum of data into categories. For example, you could find the ages of everyone in a city. You would get ages of 0, 1, 2, 3, etc. However, rather than plotting every age, you could make categories. Everyone ages 0 through 18 could be put into the first category. Ages 19 through 35 could be the next group. Ages 36 to 65 could be the next group. Then 66 to infinity could be the final group. Then you'd make a histogram with one column for each age category. The height of the column represents the number of people in that category.

Bar graphs in general can show anything. You could label each column with the name of a country, and have the height represent the gross national product of that country, or the population, or anything else.