Tuesday, April 3, 2012

Stem and leaf plot

http://mainland.cctt.org/mathsummer/josephbond/stemandplots/images/table2.gif

Stem and leaf plots are great for presenting qualitative data in a way that is easy to visualize and understand, a lot like a histogram. This stem and leaf shows infant mortality rates per 1,000 live births in Western Africa.

Box plot

http://www.stat.yale.edu/Courses/1997-98/101/boxplot.gif

Boxplots are made to summarize data that is measured in intervals. This box plot shows winning numbers in a lottery three different times. The median for each set is shown by the black line in the red boxes. In this plot, the medians are all nearly the same.

Histogram

http://upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Histogram_of_arrivals_per_minute.svg/250px-Histogram_of_arrivals_per_minute.svg.png

Histograms are designed to show distribution of data in a way that makes it easy for people to compare visually. This histogram shows the frequency and arrivals per minute. For example at 6 arrivals per minute there was a frequency of about a 6 or 7.

Sunday, April 1, 2012