Forfatter av avsnitt: Danielle J. Navarro and David R. Foxcroft

Utelatelser innenfor de temaene som dekkes

Even within the topics that I have covered in the book, there are a lot of omissions that I would like to redress in a future version. Just sticking to things that are purely about statistics (rather than things associated with jamovi), the following is a representative but not exhaustive list of topics that I would like to expand on at some time:

  • Flere typer av korrelasjoner: I kapittelet Korrelasjon og lineær regresjon snakket jeg om to typer korrelasjoner: Pearson og Spearman. Begge disse metodene for å vurdere korrelasjon er anvendelige i tilfeller der du har to kontinuerlige variabler continuous og ønsker å vurdere sammenhengen mellom dem. Hva med tilfellet der begge variablene er på en nominalskala nominal? Eller når den ene er på en nominalskala nominal og den andre er kontinuerlig continuous? Det finnes faktisk metoder for å beregne korrelasjoner i slike tilfeller (f.eks. polykorisk korrelasjon korrelasjon), og det hadde vært fint om disse var inkludert.

  • More detail on effect sizes. In general, I think the treatment of effect sizes throughout the book is a little more cursory than it should be. In almost every instance, I have tended just to pick one measure of effect size (usually the most popular one) and describe that. However, for almost all tests and models there are multiple ways of thinking about effect size, and I would like to go into more detail in the future.

  • Dealing with violated assumptions. In a number of places, I have talked about some things you can do when you find that the assumptions of your test (or model) are violated, but I think that I ought to say more about this. In particular, I think it would have been nice to talk in a lot more detail about how you can tranform variables to fix problems. I talked a bit about this in the sections Transforming variables and Matematiske funksjoner og operasjoner, but the discussion is not detailed enough I think.

  • Interaction terms for regression. In chapter Faktoriell ANOVA, I talked about the fact that you can have interaction terms in an ANOVA, and I also pointed out that ANOVA can be interpreted as a kind of linear regression model. Yet, when talking about regression in chapter Korrelasjon og lineær regresjon I made not mention of interactions at all. However, there is nothing stopping you from including interaction terms in a regression model. It is just a little more complicated to figure out what an “interaction” actually means when you are talking about the interaction between two continuous predictors continuous, and it can be done in more than one way. Even so, I would have liked to talk a little about this.

  • Method of planned comparison. As I mentioned this in chapter Faktoriell ANOVA, it is not always appropriate to be using a post-hoc correction like Tukey’s HSD when doing an ANOVA, especially when you had a very clear (and limited) set of comparisons that you cared about ahead of time. I would like to talk more about this in the future.

  • Metoder for multiple sammenligninger: Selv om vi snakker om post-hoc-tester og multiple sammenligninger, skulle jeg gjerne ha snakket mer detaljert om metodene, og om hvilke andre metoder som finnes i tillegg til de få alternativene jeg nevnte.