Survey Tabulation > Cell contents > Statistical formulae > Summary statistics of numeric variables
 
Summary statistics of numeric variables
Notation
The following table shows additional notation used in the remainder of this topic except where stated otherwise.
Notation
Description
Value of the variable for case i.
Weight for case i
Number of cases
Sum of the weights for the first i cases
Mean for the first i cases
The following table provides the formulae used by UNICOM Intelligence Reporter - Survey Tabulation to calculate the cell contents that are dependent on a numeric variable, with the exception of percentiles, the formula for which is shown below the table.
Item
Formula
Mean
Sum
Minimum
Maximum
Range
Mode
Value of X j that has the largest observed frequency. If there are several modes, the first one encountered in the data is selected.
Median
The median is the 50th percentile. See Percentile below.
Variance
Standard deviation
Standard error
Percentile
UNICOM Intelligence Reporter - Survey Tabulation uses one method for computation of percentiles. Let
where p is the requested percentile divided by 100, and k 1 and k 2 satisfy
Then
Let x be the pth percentile; the definition is as follows:
Note Quantum uses the Aempirical (Empirical Distribution Function with Averaging) formula to calculate median. The expression is:
See also
Weighting
Rounding values
Statistical formulae