I'm a biology PhD student dealing with ordinal data (scoring of a medical effect: 0–3 points) for the first time and I'm looking for information regarding differences in treating ordinal numbers in
- calculating Mean, Median, SD, SEM etc.
- performing significance tests between two ordinal datasets
- calculating correlations
For the last point, I stumbled across the Spearman's coefficient. So far so good, but can I treat ordinal datasets the same way as cardinal datasets in terms of Mean, Median, SD, SEM and significance tests?
Any comments appreciated, I'm also happy with good literature, if it's not too hard to understand.