If you do not pass a list of columns to calculate the descriptive statistics over, PySpark will return the statistics for each and every column in your DataFrame. Check out the following snippet:

descriptive_stats_all = no_outliers.describe()
descriptive_stats_all.show()

It will result in the following table:

As you can see, even the string columns got their descriptive statistics which are, however, fairly questionable to interpret.