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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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Averaging a linear or nonlinear function treatment

In a hypothetical PET study, my sample consists of a clinical population which exhibit brain hypermetabolism. I divide my sample into two homogenous groups. One receives a treatment whereas the other ...
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2answers
58 views

Bounds on skew and kurtosis of IQ

The question of whether IQ is Normally distributed, or instead follows e.g. a Pearson type IV distribution, has been debated since at least the 1910s. The quotient- and deviation-based definitions ...
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1answer
39 views

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

Background : There seems to considerable debate regarding the output of psychological research lacking a) appropriate, rigourous statistical treatment of data b) replicability As a second year ...
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1answer
50 views

Questions on Interpreting Factor Analysis Results and Scores

I am trying to learn factor analysis and I thought it would be a good idea to try and very poorly "mimic" the computation for IQ scores with a dataset of dummy values as a way to "learn by example". ...
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Is it okay to use “fixed number of factors” in EFA after contradicting results from MAP test and eigenvalues?

I need help with my data analysis. I am using a non-validated translated questionnaire in my survey. The purpose of it is not to validate the measure in a different language and its construct validity,...
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1answer
430 views

Is writing ability associated with IQ or intelligence?

Is greater ability to write well i.e. analysis of books/literature/research papers associated with higher I.Q. scores? Statistically speaking, is writing ability normally distributed like I.Q. is?
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22 views

Ability of fixed-effects analyses to enable generalisation of results

Is it correct to say that, when making inferrence on the results of an experiment, using a random-effects (RFX) rather than a fixed-effects (FFX) model merely makes the results more generalisable, as ...
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1answer
39 views

What statistics can compare individual survey responses & others that were measured as a group (from which we need to extract individual responses)?

The organization I belong to studies indigenous populations through primarily survey research. One study for example aims to identify the relationship between culture and the evaluation of odors. We ...
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1answer
37 views

Which experimental design is this? Factorial vs within groups

I have two independent variables (age and gender) and one dependent variable (the results of a questionnaire using a Likert scale). I'm trying to see whether age and/or gender have an effect on the ...
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Still-high spatial resolution of (smoothed) fMRI activation clusters!

There appears to be a mismatch between how fMRI results are presented graphically and how we know the analyses are normally done. Say we do a group-level analysis for some contrast of interest, and ...
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1answer
32 views

When to use standard versus moderator regression techniques for the most parsimonious approach?

I know how to run multiple regressions (SMR, HMR, and MMR) in SPSS but I'm still a little vague on when it's appropriate to use each of them to achieve the best and most parsimonious result. (SPSS ...
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46 views

How to statistically test whether parents and children share similar humor styles?

I have data from children and their parents on their humor styles (using the Humor Styles Questionnaire by Martin (2003)). For the adult version: It's a 32-item measure, with 4 subscales for each ...
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1answer
51 views

In fMRI analyses, what is the t-test actually comparing?

In a 1st-level fMRI analysis, it is unclear to me what the t-test performed for each voxel is actually comparing. I've seen this being described in one of two different ways: The t-test estimates how ...
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53 views

Statistic analysis on EEG data - how to deal with it properly?

Let's assume that I have a datasheet looking like that: ...
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1answer
32 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 ...
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21 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 ...
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1answer
198 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 ...
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1answer
77 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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21 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 ...
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1answer
32 views

What is restriction of range correction formula when you don't know standard deviation of unrestricted group?

What is the restriction of range formula if you don't know the standard deviation of the unrestricted group is? For instance, you run a selection process, 1st stage is a cognitive ability test and ...
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3answers
90 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 ...
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2answers
131 views

Can people act randomly? [duplicate]

Let's imagine an experiment. We will tell N normal people that they need to act randomly in the Rock–paper–scissors game (in this game Game Optimal Strategy is to choose an action with uniform ...
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1answer
34 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 ...
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1answer
58 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 ...
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1answer
263 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 ...
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155 views

Testosterone in women vs. estrogen in men?

It is known that women with higher estrogen are more likely to find men with higher testosterone as more attractive. Positive feedback is also known. But are women with higher testosterone level are ...
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1answer
270 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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1answer
196 views

Does Emotional Intelligence (EQ) demonstrate the Flynn Effect?

The Flynn Effect is a well-known phenomenon whereby Intelligence Quotient (IQ) test scores among the general public seem to rise over time. Does Emotional Intelligence (EQ) demonstrate the Flynn ...
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2answers
81 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 ...
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1answer
45 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, ...
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1answer
91 views

Are there any tests for one's belief or philosphy?

I know of the varying types of personality tests and I find them interesting (specifically HEXACO due to it having multiple facets to expand its 6 main factors and I believe it is open-source or free ...
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49 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 ...
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2answers
749 views

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

I have several response times from participants in a mental rotation task. I'm really puzzled how to get the best distribution model to fit my data. I had checked several ones with the fitdistrplus::...
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21 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 ...
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1answer
443 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 ...
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26 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, ...
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1answer
59 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 ...
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1answer
34 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 ...
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1answer
585 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 ...
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1answer
121 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 ...
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1answer
60 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 ...
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1answer
266 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 ...
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1answer
520 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 ...
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1answer
26 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 ...
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2answers
59 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 ...
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0answers
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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 ...
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1answer
88 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....
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873 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 ...
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3answers
58 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 ...
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1answer
56 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 ...