Questions tagged [psychology]

Psychology is an academic and applied discipline that involves the scientific study of mental functions and behaviors.

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1answer
22 views

How do I report results from a Tukey post hoc analysis?

I examined all possible comparisons in the Tukey test (here is the chart - sorry it's a little unclear) https://scontent.fybz2-1.fna.fbcdn.net/v/t1.15752-9/...
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0answers
37 views

Cronbach's Alpha with repeated missing values

I would like to use Cronbach's Alpha to check the fiability or internal consistency of a cognitive task. The task has a certain number of trials which were coded with zeros (incorrect trial) and ones (...
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2answers
59 views

Difference in Significance for a T and F test

After conducting a one way ANOVA, an F-test indicates that I should retain the null hypothesis (no two means differ), but the t-test (in line with the theory) tells me that the groups I tested are ...
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0answers
5 views

How do I appropriately take into account baseline item variance in a two-phase experimental design?

We are running a study with a two-phases experimental design: in the first phase, we ask subjects for intuitive scores about our items. In a second phase we ask people for an estimate that ...
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0answers
6 views

Dyadic data: Should I randomize Ps to condition at level of individual, or level of dyad?

I am about to launch a 2 (within-subjects) x 2 (within-subjects) x 2 (between-subjects) experiment in which ~50 pairs of undergraduate students will interact with one another. The within-subjects ...
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1answer
39 views

lmer fixed effects coefficients: which is the term of comparison for levels? [closed]

I have a lmer model with two within factors lmer (variable ~ time * condition + (1|id), data= df) with time having 2 levels (<...
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0answers
9 views

Number of trials needed in a 2AFC to test for significant difference from chance

I am running a two-alternative force choice task (2AFC) in which subjects indicate which of two intervals they believe a stimulus was present in. Some subjects will be blind and as such, we would ...
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1answer
36 views

Mixed-effects models for within-subject psych experiment (in Stata)

I have a question about how to best analyze data from an experimental psychology study. Briefly, 250 participants were asked to assign four different pictures (Pictures A - D) to two different ...
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1answer
34 views

Difference between “distractors” and “foils”

What is the difference between "distractors" and "foils" in experimental design in psychology?
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6 views

Two-way MANOVA univariate results interpretation

I have ran a 2 way MANOVA which has 2IVs (each with 2 level) and 8 DV's so my multivariate analysis is not significant but i do have significant univariate results fo 2 DV's however i am confused as ...
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1answer
33 views

What statistical analysis should I use for comparing multiple variables at different time frames? (psychology experiment)

I'm planning a longitudinal psychology experiment where I want to compare levels of different variables over the course of an 8-week treatment. i.e. I want to see any increase/decrease in variable A, ...
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0answers
16 views

How to test the validity of Fitt's law in R

I would like to use the Fitt's Law to test some hypothesis. Anyway, it's the first time I use it, and I have some doubts. Then aim of my experiment is to test if in a certain situation the Fitt's law ...
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1answer
88 views

Post-hoc testing for cumulative link mixed-effects model with interactions in R

I'm a resident physician working on my doctor's thesis and I'm trying to analyse data from a survey with R. I have basic mathematic and rookie statistics skills. Participants of the survey have been ...
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1answer
32 views

what type of research design should I choose?

I am trying to do a research proposal where I planned on doing a pretest-posttest experiment on 2-3 groups of subjects (measure baseline indicators of anxiety, depression, self-esteem, body ...
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1answer
30 views

Is it legitimate to use PCA on scale totals (rather than individual questions) to uncover latent variables (Social Science/Psychology)?

I believe a latent self-control variable may be at the root of plenty of the variation I see in my dependent variable. However, I am using a secondary dataset and do not have access to individual ...
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0answers
660 views

Proper way to plot confidence interval under normal distribution curve?

I write a small program which calculates a confidence interval for a given norm value. The output is then visualized by plotting the confidence interval and the corresponding hypothetical norm value ...
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1answer
153 views

Strategies for predicting 100 binary choices given the previous 100

Background As an experimental psychologist, I've long had an interest in binary decision-making tasks. Typically, in such a task, I manipulate a few properties of some hypothetical or real decision, ...
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0answers
107 views

Multilevel Mediation Analysis (2-1-1-2 mediation) in R

I aim to perform a 2-1-1-2 mediation analysis with Trait A being the IV, Trait B being the DV (both on Level 2) and both State A and State B being two Level-1 mediators. I assume the Level-1-mediators ...
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0answers
46 views

Ordinal logistic GEE sample size estimation

I am looking for ways of doing power analysis for ordinal logistic GEE (currently in SPSS, but open to attempting R or something else). My understanding is that this will not be possible in software ...
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0answers
12 views

Is it correct to a total Cronbach´s alpha analysis to a tridimensional scale?

There´s a statement that says that Cronbach´s alpha assumes unidimensionality. In that sense, is it correct to calculate a global alpha? I mean, by including all 3 dimensions, and not by separating ...
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1answer
18 views

How do I find out if there is a relationship between confidence (continuous variable) and accuracy(categorical)

I am looking finding out if confidence (rated between 0 and 10) has an effect on accuracy (correct or incorrect) and am unsure what test to run. My study is looking at how line up condition (PACE ...
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1answer
68 views

How to assess the change in association between two variables?

Let's say I have an psychological experiment in which I measure two variables. I am interested to test whether these variables are related (i.e., whether they reflect related processes). I have a ...
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3answers
157 views

Direction of correlation

There are two interdependent variables - experience and fun. Using a correlation, we can only say how fun and experience are related, and the strength of the relationship. My question is how do I ...
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1answer
38 views

Using regression to determine the effect of a variable on changes to pre and post measures

I am a stats novice, using R for my psychology dissertation. Design: At T1, each participant was measured on their level of the personality trait "conscientiousness". They also reported their level ...
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0answers
176 views

Sample Size Estimation/Power Analysis Using Simulation in R

I am looking for a way to estimate the number of observations needed for a regression analysis. My hypothesised model is y_post ~ y_pre + x1*x2. My interest lies in ...
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1answer
45 views

How to Interpret Reflective Measurement Model?

Given $F$ is a latent construct (cause), and $Y_1$, $Y_2$, and $Y_3$ are the manifest (indicator) variables (effects) which are measured. Then, there are two groups of people (A and B). According to ...
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0answers
194 views

Creating scree plot before or after varimax rotation

I am performing a principal components analysis using the psych package in R. I have the results for a PCA with varimax rotation, but I can only figure out how to make a scree plot for the PCA without ...
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2answers
106 views

ANOVA vs Repeated Measures ANOVA

I have run a psychophysical experiment where there are three conditions. All participants undergo each condition. The task is to search for a target on a display and button press when found. Eye ...
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0answers
259 views

What is the best way to analyse (in SPSS) a matched group design?

I am studying cognition in juvenile sex offenders. I have two independent groups: juvenile sex offenders and juvenile non-sex offenders. I am matching these groups on 9 variables: age, gender, SES, ...
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0answers
20 views

Instrument with Positive and Negative Affect

I am planning to use an instrument "GEQ" that contains 16 items, 4 items are grouped into the following categories: a. Positive Affect b. Negative Affect c. Flow d. Challenge scale: 1: strongly agree;...
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1answer
98 views

Multisample SEM in R: Differences in significance level using UVI vs ULI

I'm a graduate student in psychology trying to examine the factor invariance of some psychological constructs worry (using a two-factor model) using Structural ...
2
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1answer
351 views

What is the correct way to add and analyse covariates in a 2x3 Mixed ANOVA in SPSS

I am trying to analyze whether different intervention groups scored differently in questionnaire measures before and after an intervention. The first independent variable is time at 2 levels (pre-...
-1
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1answer
43 views

Sample size human sciences [closed]

I will apply a questionnaire with 90 questions about the possible requests: very bad, bad, neutral, good and very good, the answers will be categorized into 8 different groups. Subsequently the data ...
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0answers
42 views

Deduction of a correlation [duplicate]

Theoretically if one variable (Black and White Imagery) does not significantly correlate with another variable (Perceived Usability), in practice (real world situation) does this mean that there is no ...
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1answer
41 views

Psychological variables: Right percentage of subjects to choose when comparing subjects depending on their level on Neuroticism (Eysenck's model)

I am trying to analyze some data regarding the relationship between Neuroticism/Stability, from Eysenck's model of personality, and ease of use (one of the dimensions of the TAM model, by Davis) when ...
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0answers
59 views

Can Latin Square combine between- and within-subject design?

I´m doing an experiment and I´m not entirely sure if my design is still the Latin Square Design. I have 2 independent variables: medium and ...
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1answer
262 views

Composite Variables for simple and multiple regression

When I am supposed to create a composite variable using the sum or the mean method? Thanks in advance, Alex
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3answers
357 views

What variables need to be controlled for in regression?

There are numerous discussions on this site concerning how to control for certain variables in regression analysis. How exactly does one “control for other variables”? How do you "control" ...
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1answer
572 views

What is the difference between “comparison” and “contrast” in psychological statistics?

What is the difference between a "comparison" and a "contrast" in psychological statistics? For example, what is the difference between multiple comparisons and planned contrast?
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4answers
468 views

How does Bayesian analysis make accurate predictions using subjectively chosen probabilities?

Since Kahneman and Tversky found that humans do not accurately assume probabilities, how can Bayes theorem use subjectively chosen probabilities to accurately predict things (like insurance policies), ...
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0answers
86 views

Why don't researchers share their raw data for better science? [closed]

Publication bias. Reproducibility problem. Abusing statistical tests. These are some of the many criticisms received by all fields of science for a long time. If I read an article in Psychological ...
12
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3answers
1k views

Is publishing work based on post hoc analysis problematic? [duplicate]

Nowadays, in the scientific domain, increasingly, people in the top position argue against doing post-hoc analysis and they advise against collecting a bunch of data and just make up a story after ...
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0answers
58 views

Can I do multiple regression on a total sample size of 30 (3 groups of 10 each)?

My data is subdivided into 3 groups each of size 10, g1 (grandparents), g2 (parents), and g3 (grandchildren). I am trying to understand the variance in level of subjective well-being (independent ...
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0answers
15 views

Can you find the variability accounted for using only the mean and s.d

I am comparing the variability accounted for from two different studies. One gives me F(obs) and the two df's right off the bat so I can calculate that easily. The other, however, only gives me the M ...
1
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1answer
58 views

EEG waves measuring statistical significance of an event

I have recently gotten into a problem with EEG activity measurement. I need to prove (or disprove) that certain event triggered a statistically significant reaction in EEG activity. I know exactly at ...
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2answers
131 views

ARIMA for measuring effect size of mood stabilizing therapy?

Hi Im doing a research project regarding self-reported mood fluctuations. during a one year psychotherapy for 80 different subjects (they are in psychiatric treatment. The patients has trouble ...
1
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1answer
87 views

To use t-test with log-values or U-test with initial values

My sample size is in the test group=11 and control group=19. I'd like to compare if there is a difference in hair cortisol concentrations (continuous variable). My main question is whether to use t-...
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1answer
28 views

Ordinal or Scale?

I have collected data using two questionnaires for depression and eating habits - I have added together the variables for each construct and have one number for each variable for each participant. Am ...
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1answer
38 views

Hierachical Regression, accepting/ rejecting hypothesis?!

I have conducted some research and I had three hypotheses. My third hypothesis was 'stress and social support will be predictors of anxiety and depression scores when controlling for age, gender, year ...
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1answer
288 views

Log transform before bootstrapping?

Background: I’m exploring if hair cortisol levels (pg/mg) are related with executive functions like working memory (measured on WISC-scale), inhibition control (BRIEF-scale) and attention shifting (...