[Mick Kountras]

Thanks for your reply Nick.
Would you be so kind as to indicate me documentation introducing me with these basic concepts ?
Besides, if you could reply to my previous questions (you or someone else), it would be perfect.

[Dirk Enzmann]

I am not sure whether I understand you correctly meaning that you really never had any introductory textbooks on statistics in your hands. Considering your question seriously, I recommend to take a few weeks delving into the basics of inferential statistics by using books that also have examples you can replicate using Stata. Browsing through the Stata bookstore searching for books on introductory statistics will help. For example, the textbook by Dietz and Kalof (2009) is a good starting point - especially chapters 7 to 10. Google books allows you to browse through parts of the book to see whether it meets your level of understanding.

[Mick Kountras]

I never said that but I am interested in all sources of statistics knowledge. But I would have preferred an answer to my question regarding seasonality => how can we prove the absence (or not) of seasonality in a series.

[Nick Cox]

You did get answers and it is puzzling if not absurd to imply otherwise. But your main reaction is to say or to show that you don't understand them. Sorry about that, but do please re-read the Advice Guide, which explains an expectation of having read basic literature at the level you are working at. The first level of misunderstanding to peel away is the idea that statistical methods offer proof.

[Dirk Enzmann]

I can only support Nick's advice to start reading basic literature (which actually is a requirement). To let you get an impression on what this involves when it comes to the issue of testing (not (dis)proving!) seasonality, see for example the discussion in chapter 3 of: Rau, R. (2007). Seasonality in Human Mortality: A Demographic Approach. New York: Springer.

[Mick Kountras]

Dear friends,
thanks for contributing. It happens sometimes in the industry world that you need methodological insight rather than lectures on a topic.
Anyway, I will try to consult your link to become enough smart to discuss with you.