9 votes

Calculating d-prime

To calculate $d'$ you need to know two things: the hit rate and the false alarm rate. The hit rate is the proportion of trials where the stimulus was present and the subject responded that the ...
8 votes

Is most of Kahneman's 'Thinking fast and slow' not supported by evidence/non replicable?

This is complicated. There's no easy answer, but the outlook for replicability/reproducibility of a lot of the empirical evidence is not great. The R-index (that the blog authors use to rank the ...
  • 529
7 votes

Can I use data taken in a 5-point Likert Scale, and convert it as if it were taken as a 4-point Likert?

In general, from my extensive experience, using a four or a five point response scale is not going to change much the psychometric properties of a typical psychological self-report scale (e.g., ...
7 votes

What is the rationale for the normal distribution of intelligence?

Short answer IQ scores are distributed normally, because they follow the central limit theorem. Background When we measure IQ scores in sufficiently large populations, they will be normally ...
  • 20k
6 votes
Accepted

How should results from linear mixed models (LMMs) be reported?

The APA style manual does not provide specific guidelines for linear mixed models. Additionally, a review of studies using linear mixed models reported that the psychological papers surveyed differed '...
6 votes
Accepted

How to know whether a methodological technique is quantitative or qualitative?

It's important to distinguish between measures and analyses, because only analyses can be quantitative or qualitative, not measures. Measures are, essentially, systematic processes by which we ...
6 votes

How to know whether a methodological technique is quantitative or qualitative?

ANOVA and t-tests are statistical tests for significance and therefore quantitative. The other mentioned items are scales (adding numbers to a certain choice) and therefore they can be considered as ...
  • 20k
6 votes

Which statistical tests to use when analyzing NASA TLX?

In Stevens' levels of measurement framework, the NASA-TLX is an ordinal scale, not an interval scale, because there is no way to know a priori how much "workload" each point corresponds to. In other ...
5 votes
Accepted

How should I report results of a likelihood ratio test?

General reporting recommendations such as that of APA Manual apply. One should report exact p-value and an effect size along with its confidence interval. In the case of likelihood ratio test one ...
  • 309
5 votes
Accepted

What variables allow one to empirically and scientifically quantify trends for learning curves?

Short answer In psychophysical tests, often %correct rates are determined. Hence, training effects are often measured by determining correct rates. The ultimate outcome measures can be wildly variable,...
  • 20k
5 votes
Accepted

Should I look at the data of an experiment before the dataset is complete?

Short answer From an ethical standpoint, not including interim evaluations may be bad practice. Background I will start off with a more extreme case than in your question example, just for ...
  • 20k
5 votes

Should I look at the data of an experiment before the dataset is complete?

gjacob is correct that optional stopping is a common research degree of freedom, and one that has a considerable and unfortunate intuitive basis. Yet, depending on the context of your research, AliceD'...
  • 286
5 votes
Accepted

What are the benefits of using all 30 personality facets in multiple regressions compared to just including hypothesised facets?

I wrote a paper that focuses on this question (Anglim & Grant, 2014; pre-print is https://osf.io/g8kbj/download). In short, if you're interested in estimating how well facets predict an outcome, ...
5 votes
Accepted

Recommended resources (journals, blogs, etc) for nurturing a background of statistical/methodological rigour in behavioural science research?

There are various loosely-defined 'camps' among reform-minded methodologists, so you probably want to try to follow a representative of each. Andrew Gelman is a prominent landmark in this area, and ...
5 votes
Accepted

Recent Peer Review Studies on How Many Have Narcissistic Personality Disorder

While not a peer-reviewed study per se, but the DSM-5 says that the prevalence of Narcissistic Personality Disorder in the population is 6.2%, or approximately one out of sixteen members of the ...
  • 272
4 votes

Which statistical tests to use when analyzing NASA TLX?

I am particularly concerned with whether or not the task load index could be considered an interval variable, Yup. This is a fundamental assumption people make when constructing, administering ...
  • 1,227
4 votes
Accepted

How common is the form of amnesia depicted in fictional works?

What you are referring to is something called dissociative fugue. It is characterized as an official psychiatric disorder and dissociative disorder in the DSM-5, and its prevalence has been estimated ...
4 votes

Calculating d-prime

The index of sensitivity $d'$ is typically defined in terms of two equal variance normally distributed random variables with means $\mu_s$ and $\mu_n$ and standard deviation $\sigma$: $$d'=\frac{\...
  • 2,627
4 votes

Why so few subjects in psychophysics?

It is partly as you already guessed, because the phenomena that are studied don't vary as much between individuals. This doesn't necessarily mean that individual differences in perception are smaller, ...
  • 2,553
4 votes

in R : How to check RT's for ex-gaussian fit with the fitdistrplus package

To answer the question relating to start values for the parameters for use with fitdist: I would like to check for an ex-gaussian distribution fit (GAMLSS ...
  • 141
4 votes
Accepted

How do scientists/psychologists deal with conflicting experiment results?

Meta-analysis is the statistical practice of combining results across studies in a principled way. Meta-analyses weight the relative strength of evidence from different studies to generate an overall ...
  • 6,417
3 votes

How should results from linear mixed models (LMMs) be reported?

As an update, this paper may be helpful, though it comes from the medical field. References Monsalves, M.J., Bangdiwala, A.S., Thabane, A. et al. LEVEL (Logical Explanations & Visualizations of ...
3 votes

How should I report results of a likelihood ratio test?

The likelihood ratio test is distributed as χ²with degrees of freedom = the change in degrees of freedom between the two models. So, to give an example dropping one parameter from a model, you would ...
  • 243
3 votes

Attributing change in DV to IV manipulation: between-groups (control group) vs mixed-model (pre&post measure)

There's a short straightforward answer, and a more nuanced answer. The short answer is that people were randomly assigned to the two groups. Any baseline differences between people will be equally ...
3 votes

What tools are available for EEG analysis on the R platform?

For the sake of completeness: eegkit, see https://cran.r-project.org/web/packages/eegkit/index.html For "historical purposes" perhaps the following could also be of interest, although development ...
  • 131
3 votes

What tools are available for EEG analysis on the R platform?

I was searching for alternative when I fell on this post. Here are a few others eegUtils , the same author has a blog that might be of interest to you for further reading here I also found eegAnalysis ...
  • 151
3 votes

Fitting a psychometric function when data does not lend itself to a sigmoidal fit

What you are looking for is called Hierarchical, Multi-level or Random-effects model. In your particular case the solution is a hierarchical logistic regression. Assume $y_{st} \in \{0,1\}$ is the ...
  • 309
3 votes

Which R packages have good collections of psychology datasets?

Another good set of psychological datasets can be found on the website of the European Journal of Psychological Assessment: https://us.hogrefe.com/products/journals/ejpa/special-features There are ...
3 votes

How to measure precision in classical test theory framework?

'Precision' in classical test theory Most accounts of classical test theory do not have a notion of precision as such, but occasionally, reliability may be called precision instead. The relationship ...

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