I'm totally newbie in psychometrics but starting from a research paper with full data I would like to understand:

  1. how to calculate if the sample size is representative;
  2. how to calculate reliability and validity of two questionnaires (1 composed by 12 items with Likert scales distributed in 5 dimensions and 1 with 6 Likert items on 3 dimensions). Each questionnaire has been administered just once during the data gathering phase.

Could you please suggest me some Internet resources (and/or good books) to learn how to do that?

I would prefer to use R for data analysis.


1 Answer 1


@gianluca78, It would be my recommendation that you explore the psych package in R. I have been using it for years and the author has done an incredible amount of work to put it together and to maintain it.

It is a large field. Congratulations on having the curiosity to explore it in depth.


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