# Displaying Descriptive Statistics for Missing Values

Univariate Statistics

Univariate statistics can help you identify the general extent of missing data. For each variable, the following are displayed:

- Number of nonmissing values
- Number and percentage of missing values

For quantitative (scale) variables, the following are also displayed:

- Mean
- Standard deviation
- Number of extremely high and low values

Indicator Variable Statistics

For each variable, an indicator variable is created. This categorical
variable indicates whether the variable is present or missing for
an individual case. The indicator variables are used to create the
mismatch, *t* test, and frequency tables.

**Percent mismatch.** For each pair of variables, displays
the percentage of cases in which one variable has a missing value
and the other variable has a nonmissing value. Each diagonal element
in the table contains the percentage of missing values for a single
variable.

**t tests with groups formed by indicator variables.** The
means of two groups are compared for each quantitative variable, using
Student's *t* statistic. The groups specify whether a variable
is present or missing. The *t* statistic, degrees of freedom,
counts of missing and nonmissing values, and means of the two groups
are displayed. You can also display any two-tailed probabilities associated
with the *t* statistic. If your analysis results in more than
one test, do not use these probabilities for significance testing.
The probabilities are appropriate only when a single test is calculated.

**Crosstabulations of categorical and indicator variables.** A
table is displayed for each categorical variable. For each category,
the table shows the frequency and percentage of nonmissing values
for the other variables. The percentages of each type of missing value
are also displayed.

**Omit variables missing less than n % of cases.** To reduce
table size, you can omit statistics that are computed for only a small
number of cases.

To Display Descriptive Statistics

This feature requires the Missing Values option.

- From the
menus choose:
- In the main Missing Value Analysis dialog box, select the variable(s) for which you want to display missing value descriptive statistics.
- Click Descriptives.
- Choose the descriptive statistics that you want to display.