In our previous discussion of distributions of data, and how to understand them with histograms, we were always working with one variable at a time. Some of the variables we looked at were the number of births in each state, the number of births to teens in each state and the writing scores of individuals. We learned that we can understand some things about the variable we are studying by looking at the distribution of the data as revealed in the histogram. These data report the values of a number of variables measured on 41 cities. The numbers are averages of data collected from 1969-1971.
Lets look at some of the histograms.
Raindays is relatively bell shaped though the tail on the low end seems a little long. The bottom three cities are Phoenix, Albequerque, and San Francisco. The number of days of rain is relevant to studying the pollution in the cities because the rain washes the pollution out of the sky. Wind is also relatively bell shaped in the middle except it has a second peak and a little bit longer tails than we would expect. The three windiest cities are Witchita, Buffalo and Milwalkee.