I am a Math Phd student and a Teaching Assistant for Statistics in Psychology Deparment.
The problem I have is to determine the level of measurement. Let me first present the question:
Assume that a researcher measured self-esteem and obtained the scores 49, 53, 67, 20, 27, 36, 49, 27, 61, and 28. Determine the level of measurement...
I believe it should be an ordinal measurement, since there is no guarantee on how people perceive the scale and hence it is questionable to talk about differences. However, we consider it as an interval scale.
My apologies for a simple question. I really appreciate if you can provide some references for me to read and learn more so that I can guide students better.
Thank you very much.