Questions tagged [statistical-power]
Is a property of a hypothesis testing method: the probability of rejecting the null hypothesis given that it is false, i.e. the probability of not making a type II error. The power of a test depends on sample size, effect size, and the significance ($\alpha$) level of the test.
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Calculating Minimum Detectable Effect (MDE) in observational causal inference with binary outcomes: How to account for covariate adjustment?
I am designing a causal inference analysis using observational data and I am trying to determine the sensitivity of my study design given a fixed sample size.
Study Details:
Goal: Estimate the Average ...
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Is a linear mixed-effects model appropriate with only one observation per task per participant and n=13 per condition
I am analysing data from a pilot VR study with a between-subjects manipulation of arousal (High, Neutral, Low), with 13 participants in each condition. Each participant completed three different VR ...
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What is the design effect factor for an experiment with crossed random intercepts?
I want to know what is the design effect factor of a crossed study like this where we have:
N=100 participants
15 items
Each participant assigned to treatment or control
Each participant does 7 ...
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Contigency tables and Fisher exact test for multivariable binary data
I am looking for guidance on the appropriate statistical procedure/protocol to follow in the following situation (the context is a metagenomic study):
The data consists of a table $\mathbf{X}$ of ...
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Does this study need a power analysis?
I have an investigator who is planning to study a new treatment on a group of 40 patients. He believes that 25% of people will dropout, mostly due to lack of insurance coverage. His goal is to have 70%...
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Can an estimated marginal mean be used to calculate an effect size for a power analysis?
I'm interested in calculating the required sample size for detecting a future hypothetical 30% increase in a marginal mean from a model based on pilot data (accounting for covariates and random ...
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Sample size calculation for an outcome with multiple non-exclusive categorical responses
I've been asked to advise on a sample size calculation for a survey where the primary question of interest takes the following form:
Which of the following factors would influence your decision about ...
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Combining prior on effect size with new effect size estimate (Bayesian)
CONTEXT
I am a researcher planning experiments. My goal is to combine a prior on the effect size from prior literature with pilot data.
SETUP
Assume I have a prior on an effect size,
$d \sim N(d_{\...
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Power of t-test with unequal sample sizes: GPower and MESS::power_t_test do not converge?
I've created two item sets with 24 items each, that I expect to differ along my outcome variable. To test this assumption before using the items in future studies, I'm planning to recruit human ...
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How is sample size specified in 2-way ANOVA power calculation in the pwr2 package? [closed]
My question is how sample size is specified in 2-way ANOVA power calculation in the pwr2 package.
In the function pwr2::pwr.2way documentation it gives an example use (source https://rdrr.io/cran/pwr2/...
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Power analysis based on non-parametric exploratory analysis
During my exploratory analysis of my data I have found interesting results. Now, my supervisor has asked me to perform a power analysis to calculate the sample size needed to investigate these results ...
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Including finite population to power analysis
I’m estimating how many patients need to be surveyed annually to detect a 10% change in over a 10-year monitoring period.
My response variable is binary (1 = yes, 0 = no).
I’ve set the significance ...
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Power analysis for a factorial design with a binary outcome
I am planning a study with a factorial design (e.g., 2×2 or 3×3), but my outcome variable is binary (yes vs. no). Most tutorials I’ve found on power analysis for factorial ANOVA assume a continuous ...
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Power function associated to a test
In class we looked at an example of application of the likelihood ratio test in the following situation: we are given a sample $X = (X_1, \ldots, X_n)$ from a distribution with pdf of the form $f(x|\...
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Which model to use for power analysis and sample size calculation for interval-censored and right-censored data?
There is a population of devices that undergo a repeating cycle of stimuli when in standby. The time in standby mode is a random variable. When called upon to operate they may either fail to operate ...
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