What kind of graph should I make?

Data Literacy Project

Mini-lesson 1 (Instruction)

The best kind of graph to use depends on what kind of question you are asking.

1. Variability within a group? frequency plot

2. Compare groups? 2 frequency plots or 1 bar graph

3. Correlation between two variables? scatter plot

4. Change through time? line graph

1. Variability within a groupFREQUENCY PLOTS (dot plot, histogram, box & whisker)

How much rainfall does Bangor get during the month of July?

Data source: http://www.ncdc.noaa.gov/oa/climate/stationlocator.html

Bar graph

Dot plot

FREQUENCY PLOTSDot plot, histogram, box & whisker plot

How much rainfall does Bangor get during the month of July?

(NOTE: Y-axis = counts)

2. Compare groups in a single variableTwo FREQUENCY PLOTS or a BAR GRAPH

During which month does Bangor receive more precipitation, July or September?

3. Are two variables correlated?SCATTER PLOTS

Is the mileage (miles per gallon) a car gets related to its weight?

Data source: US Environmental Protection Agency, epa.gov

4. Change through timeLINE GRAPHS

How has the rate of Chlamydia infections in Maine changed through time?

Data source: US Center for Disease Control from http://wonder.cdc.gov/wonder/help/stdm.html

5. How something is divided into partsPIE CHART or STACKED BAR GRAPH

How much of Maine’s electricity is generated by renewable fuels?

Sources of fuel for electricity generation in Maine (2010)

Data source: US Energy Information Agency (eia.gov)