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### Interpretation of Statistical Tests and the Importance of Statistical Power [duplicate]

I was planning on running a statistical test for hypothesis testing, but was confused if statistical power is important once a test is run. Looking at this confusion matrix, one would ideally set ...
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### A smaller dataset is better: Is this statement false in statistics? How to refute it properly?

Dr. Raoult, who promotes Hydroxychloroquine, has some really intriguing statement about statistics in the biomedical field: It's counterintuitive, but the smaller the sample size of a clinical test,...
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### Do underpowered studies have increased likelihood of false positives?

This question has been has asked before here and here but I don't think the answers address the question directly. Do underpowered studies have increased likelihood of false positives? Some news ...
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### Can I trust a significant result of a t-test if the sample size is small?

If my one sided t-test result is significant but the sample size is small (e.g. below 20 or so), can I still trust this result? If not, how should I deal and/or interpret this result?
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### Report power if result is statistically significant

We have submitted a paper reporting a statistically significant result. One reviewer asks us to report what is the power to detect a significant association. As there was a previous paper on this ...
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### Sample Size impact on Effect size

I have a small sample size ($n = 23$) and I ran some t-tests to see if there were any group differences (group one had $11$ participants and group two had $12$ participants). I can wrap my head around ...
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### Understanding Gelman & Carlin "Beyond Power Calculations: ..." (2014)

I am reading Gelman & Carlin "Beyond Power Calculations: Assessing Type S (Sign) and Type M (Magnitude) Errors" (2014). I am trying to understand the main idea, the main takeway, but I am confused....
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### Statistical power of my study

I am writing a paper for a journal. I have been asked to calculate the statistical power of my study. I have zero idea about how to do that. I am an engineer and never cared about this kind of ...
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### If a study finds a statistically significant difference, but later is determined to be under-powered, does it matter? [duplicate]

Thanks for any answers in advance. This question presumes a study has detected a difference between 2 groups, and has determined this difference to be statistically significant. I'm reviewing a paper ...
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### Is it wrong to trust Pearson Correlation output of r=.830 (sig at 0.01 2-tailed) with n=15?

After reading numerous articles on sample size as it relates to a Pearson Correlation, I have not found any reference to what happens if I have a small sample (n=15) but still get a strong r (.830) ...
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### power analysis using r

I am trying to calculate power for 150 samples where 75 are going to be in one group and 75 in another. I tried using the pwr package in R to get the power where I used the following code: ...
1 vote
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### Multicollinearity in Multiple Regression with SPSS

I want to run a multiple regression in SPSS with 7 independent variables but 3 of them are showing high correlation coefficients in the correlation matrix. How do I diagnose multicollinearity?
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### Is high multicollinearity always an issue in OLS?

$$Y_t = a + bX_{1,t} + cX_{2,t} + dX_{3,t} + e_t$$ A high $R^2$ in $X_{1,t} = \alpha + \beta X_{2,t} + \gamma X_{3,t} + \varepsilon_t$ will always result in a higher standard error of the $b$ ...
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### Properties of a distribution obtained by filtering normal distributed variables by the result of a t-test

Two sample t-test Consider the following t-test Let $x_1, \dots, x_n \sim N(\mu_1,\sigma^2)$ and $y_1, \dots, y_n \sim N(\mu_2,\sigma^2)$ be independent samples. Let's define The raw effect \$\begin{...
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1 vote