Questions tagged [statistics]

For questions about statistical methods that might be appropriate for certain paradigms within psychology, psychiatry, neuroscience, or cognitive science.

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4
votes
1answer
47 views

What does it mean to “control for differences in factors” when looking at gun ownership and homicide rates?

What does it mean "with control for differences in factors" in the sentence : "Several studies used cross-sectional analyses to detect a positive relationship between the prevalence of gun ownership ...
3
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0answers
34 views

Task-based fMRI dataset with very simple task (e.g. view stripes)

For my Bachelor thesis I need an fMRI dataset in order to look for causal relationships. I want to be able to confirm my work, so the causal relationships should already be known. Therefore, ideally ...
5
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1answer
487 views

What does it mean statistically for there to be significant differences in average IQ scores between racial groups?

Charles Murray (in his book, "The Bell Curve") reported that there are real differences between the mean IQ scores of different racial groups. He also points out that IQ variation within said groups ...
8
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1answer
93 views

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

What are the advantages/disadvantages of using all 30 facets (NEO PI-R; Costa & McCrae, 1992) in a multiple regression versus only using the facets that you have a hypothesis for? I see that the ...
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0answers
23 views

What is the rule that describes sufficiently large groups will have bad actors?

I once heard of a rule/law/number that described any group sufficiently large enough will have "bad" people in it. It is most often used to describe how online communities will have to deal with ...
5
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3answers
103 views

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

For a research internship I am running psychological experiments online. As it takes a while until the experiment is done (meaning that enough people participated, so that a sufficient sample size is ...
4
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1answer
68 views

Multiple-stratum intelligence models

My question concerns the mathematics of multiple-stratum models, about which I've not found much that's quantitative, so excuse my inventing my own notation to explain my thoughts. In models such as ...
1
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1answer
64 views

Calculating statistical significance in behaviour change

I have run a study on a group of 158 individuals to see if a teaching intervention can change their perceptions of scientists. Before the intervention, all the children in the study were asked to ...
8
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2answers
137 views

Reproducible meta-analysis in psychology

I am a big proponent of reproducible data analysis. In particular, I like when researchers share documents in formats like Sweave and knitr which weave statistical output (e.g., text, tables, and ...
2
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1answer
859 views

What is the rationale for the normal distribution of intelligence?

What is the rationale for the normal distribution of intelligence? I'm asking what the rationale is for saying that 68% of variance within intelligence falls within 1 standard deviation either side ...
2
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1answer
517 views

Is it possible to calculate the probability of a child having an IQ in a certain range based on their parents' IQ?

For instance, if two parents have IQs of 160, can one calculate the probability that their child has an IQ over 160?
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2answers
105 views

Examples of interventions that yield large long term effect sizes in psychology

I was listening to a podcast entitled Very Bad Wizards, hosted by two university academics. One of the hosts, namely David Pizarro who is a psychologist at Cornell made the claim that most ...
2
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1answer
48 views

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

Specifically, I am trying to quantify trends in learning for certain mediums of audio-visual communication, and what I've gathered so far suggests that there are 4 distinguishable types, being linear, ...
6
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0answers
937 views

What to do when you have a speed-accuracy trade-off in your data?

Many studies report that a speed-accuracy trade-off (SATO) did not occur in the data since there is a positive correlation between RTs and error rates. In other words, people took longer to respond ...
22
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5answers
1k views

Can response time be incorporated into signal detection theory?

In signal detection theory, one typically uses "signal" and "no signal" responses to analyze the data (that is, the analysis is based on a discrete choice for each trial, generating the four possible ...
8
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1answer
45k views

How to calculate IQ score based on raw score and adjust for age?

I am having a hard time grasping how IQ scores are calculated. I think it has something to do with their age score ratio multiplied by 100. Say I have a test that holds 30 questions. How would I ...
9
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2answers
6k views

Calculating d-prime

I'm currently working on a research that has to use and calculate D Prime values for a task where subjects are presented an image at different speeds and they have to report if they saw the image or ...
2
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0answers
68 views

Quantification of tendency for people to believe what is convenient

As a generalization, people have a bias towards believing what is convenient to them and/or doesn't challenge their worldview. I believe (though correct me if I'm wrong) this is linked to status quo ...
2
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0answers
27 views

Statistically, what are the determinants of which particular religion someone will follow?

I can look at data on smokers and recent ex-smokers to identify what variables correlate with success in quitting, or relapse. I can adjust for covariates, or leave the analysis unadjusted. I did a ...
2
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1answer
1k views

What is the difference between facets and factors?

I am wondering whether there is a difference between factors and facets. Concretely, I am doing a research about transformational leadership. My questionnaire has 8 factors which is based on a ...
1
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0answers
41 views

Correcting for individual differences in the usage (employed range) of rating scales

Experiments that collect subjective ratings (e.g. on a Likert 1-7 scale) necessarily have to account for between-subjects differences in how the range of the rating scale is used by different people, ...
1
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1answer
68 views

IQ scores - fixed raw scores vs infinite tails of the underlying normal distribution of standard scores

When taking an IQ test, if a subject responds to all questions correctly, they will achieve the maximum (raw) score, a finite number. Yet, due to the test's normalisation that takes the median raw ...
2
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1answer
37 views

Two time points, control and experimental groups: What design is it? [closed]

I managed to get myself confused on this one. So I am planning to conduct an experiment within an organization. I want to explore effects of recognition on people's motivation. Recognition will be in ...
1
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1answer
1k views

How to generate ipsative scores from a test with normative Likert-type items?

Some constructs in psychology are sometimes conceptualised ipsatively. I.e., where the sum of the scales adds up to a constant (e.g., personal values; coping styles). The aim of such measures is often ...
5
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1answer
150 views

Why so few subjects in psychophysics?

Why is it that most psychophysics experiments only use a handful of subjects (typically around five, but sometimes even four, three or two), whereas the "norm" for experimental psychology (assuming a ...
2
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1answer
68 views

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

I made an error in my qualtrics survey, and used a 5-point Likert scale, when the measure was supposed to use a 4-point scale. I have collected a lot of my data for my dissertation, and am now very ...
12
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4answers
4k views

Which R packages have good collections of psychology datasets?

The open source statistical software R has a range of contributed packages. Some of them include datasets. I teach research methods in psychology and I'm looking for interesting real-world dataset ...
4
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1answer
396 views

How to calculate the confidence interval for $d^\prime$ (d prime)?

I have an experiment with $N$ signal trials and $M$ no signal trials and I have measure the number of hits $nHit$ and the number of false alarms $nFA$. From this I can compute the probability of a hit ...
1
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1answer
1k views

How to compare IAT (Implicit Association Test) results of two different groups?

I already have the recommended algorithm to analyse IAT data. It allows to compare within-subject differences in response latency in the congruent versus non-congruent condition. However, in addition ...
3
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2answers
64 views

Group differences reflecting different use of a rating scale vs actual difference in perception

I was reading a paper that reports average ratings of chords by two different groups of subjects (trained musicians, and non-musicians). The paper makes the argument that "These group differences ...
1
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1answer
31 views

In SPSS, should you change the significance level for One way ANOVA post-hocs? [closed]

When running a one-way ANOVA, selecting "Post-hoc" and ticking "Bonferroni": There is a box at the bottom which says "significance level" and the default is 0.05. My question is: should I leave the ...
3
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0answers
21 views

How do I get calculate D1 and d1 in a multinomial processing tree model?

I've just been reading this paper and I am currently conducting an experiment for my undergraduate thesis. The experiment involves reality monitoring source memory judgments and I therefore want to ...
0
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1answer
95 views

Which is a better statistical option to compare differences across groups?

I have two groups (13 experimental and 13 control participants) performing on two cognitive tasks. I have accuracy (omissions, commissions) and reaction time measurement from each test for each person....
3
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0answers
1k views

Where can I find the norms for Raven's Standard Progressive Matrices?

I've never had my IQ measured before. After some research I decided to take the Raven's Standard Progressive Matrix test. After Googling I found this Wikipedia page. This test was linked on the ...
0
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3answers
62 views

How to random assign subjects to a group without any equipment?

I am working with a clinician and need her to randomly assign patients into one of two groups with the goal of having roughly equal numbers in both groups. The clinician does not have access to a ...
2
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1answer
58 views

How to efficiently use a statistical consultant?

I a fairly solid grasp of Statistics and have taught statistics to both undergraduate and graduate Psychology students. There are, however, sizable gaps in my knowledge and I have attempted to employ ...
0
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2answers
57 views

are statistic results of these two questions equal?

I am trying to make better user experience for my poll application and one of ideas I have for this is breaking multi choices poll to binary polls. Is statistical result of a question with these 4 ...
6
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2answers
3k views

In a forced-choice task, what proportion of responses is above chance level?

If I give a task in which there are only two response-options, and I want to categorise the participant according to their responses, what is the 'cutoff' or required proportion of one type of ...
1
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1answer
206 views

How to measure or estimate the prevalence of psychopathology in a particular school?

I wrote a research paper regarding the mental health of adolescents at a local magnet school, emphasizing the sources and affects of stress and the subsequent vulnerabilities it poses to developing ...
2
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1answer
994 views

Bootstrapping in Psychology

I am interested in bootstrap, especially how it's entering the psychologist's world. Boostrapping is used to 'omit' classical assumptions to get statistics. Bootstrapping starts with creating new ...
2
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2answers
378 views

cleanIAT function in R IAT package

Has anyone used cleanIAT (function in IAT package) to compute D-scores for their IAT data? Have you noticed any discrepancies between your D-scores and those of colleagues that used another program (e....
3
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1answer
114 views

What are some examples of psychology studies with tiny effect sizes and tiny p-values that are good for teaching?

I'm looking for examples of studies where the result is highly significant but the effect is so tiny that it is meaningless in a practical sense. These will be shared with undergraduate psychology ...
2
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1answer
61 views

What is the name for the cognitive bias that ignores that extreme symptoms always tend to get less extreme?

There are some long term diseases where the severity of your symptoms tend towards a 'normal'. So imagine plotting out the severity of the symptoms say, every day or every week, then drawing a line of ...
8
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3answers
382 views

Analysis of parameter estimates from Ratcliff diffusion model

I would like to analyze a dataset in which subjects' reaction time and error rate have been recorded. In order to account for potential speed-accuracy trade-off I am planning to make use of the ...
2
votes
2answers
318 views

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

One often sees researchers attributing a change in the dependent variable to their experimental manipulation, semingly without considering whether this change in DV occurs between or within groups. ...
2
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0answers
93 views

How can Bayesian inference improve upon logistic regression in incorporating psychometric data?

In order to estimate probability of default, banks and other financial institutions have often used logistic regression based on data involving credit history. Suppose an entrepreneur or borrower ...
7
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1answer
2k views

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

There are any number of movies and television shows based on some variation of the same premise: A character suffers some sort of mishap (the most frequent mishap being a bump on the head), which ...
8
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1answer
129 views

Are there any models of the human visual field of view taking into account head, neck and eye movements and calculating likelihood of fixation?

I would like to know if there are studies that (1) model the field of view taking into account all degrees of freedom of the head, neck and eyes and (2) if there is any probabilistic model assigned to ...
5
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1answer
166 views

Correlation between BIS and BAS responses

As a part of my lab experiment, participants had to answer questions for BIS and BAS (BAS reward, drive and fun) scales. The correlation matrix shows that BIS is significantly positively correlated ...
5
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2answers
9k views

How should I report results of a likelihood ratio test?

I'm using likelihood ratio testing to assess whether a behavioral model is a better description of my data than a simpler (so called restricted) model. How should results of such statistical tests be ...