# Store the descriptive statistics of a variable in a macro in Stata

In Stata, the `.tabstat` command computes aggregate statistics of variables such as mean and standard deviation, and its `save` option stores these statistics in a matrix. For example, to get the N, mean, and standard deviation of personal income, enter:

`. tabstat income, stat(n mean sd) save`

The `stat()` option specifies the aggregate statistics to be computed. `N` (the number of valid observations), mean, and standard deviation are stored in a matrix `r(StatTotal)`. You may check for the presence of the matrix using the `return list` command. You can also list the values of the matrix by running ```matrix list r(StatTotal)``` as follows:

```. return list

matrices:
r(StatTotal) :  3 x 1

. matrix list r(StatTotal)```

To convert the special matrix into a typical matrix using the `.matrix` command, enter:

`. matrix stats=r(StatTotal)`

Finally, to convert a scalar, for example, the mean of the variable, into a macro, enter:

`. local avg=stats[2,1]`

If you want to save the matrix as a variable, enter the `.svmat` command instead:

```. clear
. svmat stats, name(var)   ```

You may clear memory before converting the matrix. Since the matrix has only one column (3x1), you may have one variable `var1` with three observations for `N`, mean, and standard deviation.

If you have questions about using statistical and mathematical software at Indiana University, contact the UITS Research Applications and Deep Learning team.

## Related documents

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