## The forgotten statistics – Explore

I have a feeling sometimes that many user miss the informative command: Analyze – Descriptive statistics – Explore. This command, I have put some focus on during my statistical trainings as it tells you a lot about your continous (scale) variables. Here is the dialog box: And here is the result: I can see that the mean salary is 20 798 but the median is 18383, so I suspect a not normal distribution so then it’s better to present the median.

The spread is also showing a big variation from 14721 to 85182,  and the range between first and third quartile is 5197 for example.

As many statistical test require test for scale variables that follow a normal distribution, so that’s something that we study on the statistics training. So how can you figure out that by looking on some “strange” numbers at skewness?

Why don’t have a look on the help? Just double click the table, and then right click the Word (here “Skewness”): So as the skewness value 4.107 is MORE than twice its standard error (0.077), we say that this distribution is very skewed. How is the skewness formed, here we have a long right tail as the value 4.107 is positive. So because of this skewness this means that we have to be careful to use mean values in tests like t-test, but rather nonparametric tests if we want to compare salaries between 2 groups like male and female. But to be more specific, you should study the skewness for EACH group, so one for male and one for female.