Using JMP - SAS

Chapter 8 Summarize Data 239
Summarize Columns
• Mean Is the arithmetic mean of a column’s values. It is the sum of nonmissing values (and if defined,
multiplied by the weight variable) divided by the Sum Wgt.
• Std Dev Is the sample standard deviation, computed for the nonmissing values. It is the square root of
the sample variance.
• Min Is the smallest nonmissing value in a column.
• Max Is the largest nonmissing value in a column.
• Range Is the difference between Max and Min.
• % of Total Is the percent of the total count for each group. Or, if you have so specified, the percent of
nonmissing values of the column to the total count for each group.
• N Missing Is the number of missing values.
• Sum Is the sum of all values in a column.
• Sum Wgt Is the sum of all weight values in a column. (See “Assign Column Properties” on page 151 in
the “Set Column Properties” chapter.) Or, if no column is assigned the weight role, Sum Wgt is the
total number of nonmissing values.
• Variance Is the sample variance, computed for the nonmissing values. It is the sum of squared
deviations from the mean, divided by the number of nonmissing values minus one.
• Std Err Is the standard error of the mean. It is the standard deviation divided by the square root of N.
If a column is assigned the role of weight, then the denominator is the square root of the sum of the
weights.
• CV (Coefficient of Variation) Is the measure of dispersion, which is the standard deviation divided by
the mean multiplied by one hundred.
• Median Is the 50th percentile, which is the value where half the data are below and half are above or
equal to the 50th quantile (median).
• Quantiles Gives the value at which the specific percentage of the argument is less than or equal to. For
example, 75% of the data is less than the 75th quantile. The summary window has an edit box for
entering the quantile percentage that you want.
Example of Creating a Summary Table
Suppose a researcher is working with Companies.jmp, which groups companies by Type and Size. Follow
along with this next example by opening Companies.jmp from the Sample Data folder that was installed
when you installed JMP.
Suppose the researcher wants to:
• Create a table that shows the average profit per employee for small, medium, and big computer and
pharmaceutical companies. In other words, create a table that contains a row for each size company and
a column for the mean profit per employee of each type of company.
• Create it so the cells hold the mean for the subgroup (defined by the intersection of the row and
column).
1. Open the Companies.jmp sample data table.
2. Select Tables > Summary.