Testing Normality in SAS, STATA, and SPSS
Hun Myoung Park · 2004
The frequently used descriptive plots are the stem-and-leaf-plot, (skeletal) box plot, dot plot, and histogram. When N is small, a stem-and-leaf plot or dot plot is useful to summarize data; the histogram is more appropriate for large N samples. A stem-andleaf plot assumes continuous variables, while a dot plot works for categorical variables. A box plot presents the 25 percentile, 50 percentile (median), 75 percentile, and mean in a box. If a variable is normally distributed, its 25 and 75 percentile become symmetry, and its median and mean are located at the same point exactly in the middle.