# Questions tagged [f-test]

Any hypothesis test in which the statistic has an F distribution under the null hypothesis.

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### Why does anova F-test give different results for a categorical variable added as factor and as continuous?

I'm comparing the addition of a variable in my linear model using R and "anova F-test": anova(fit1,fit2) What I noticed is that this F-test produces different ...
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### Does the F-Test (var.test in R) assume independence of observations?

I've looked online but I can't seem to find an answer. Basically I'm comparing data from two groups, disease and control, and from each induvidual there's two observations. I want to compare the ...
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### Deriving the F-test for a complex comparison

I would like to clarify a passage from Maxwell & Delaney, Ch.4 Extension in which the authors explain how to perform an F-test for a complex comparison. In what follows, the coefficients $c_j$ ...
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### Multivariate Bayesian Testing with an F-test

In Bayesian statistics a standard way to perform a Lindley significance test for the hypothesis $\theta=\theta_0$, where $\theta_0$ is the suggested value for $\theta$ at the $\alpha$ level of ...
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### Interpreting var.test results in R

I am trying to learn F test and on performing the inbuilt var.test() in R, I obtained the following result with ...
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### Finding value of f statistic to test for difference between treatment means given the following table

Im not really good with statistics and cant really find a way to answer this question. Finding value of f statistic to test for difference between treatment means given the following table.
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### Goodness of fit. How to evaluate if polynomial of order n+1 gives statistically better fit than polynomial of order n?

I fit polynomials with increasing order to some data. What is the best way to evaluate if the additional parameter of polynomial of order n+1 provides a statistically significant better fit than the ...
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### How would I determine statistical significance for ad impressions?

I'm programatically adding keywords to bid on. Some keywords will trigger ads and impressions, and some impressions will trigger clicks. Clicks / impressions = CTR (click-through-rate). Clicks cost. ...
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### How should I treat F test if one of variances is equal 0?

I have two groups with 20 elements in each. In one group variance is equal 0. I want to do f-test. Can I? And how should I interpret results (in this case)?
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### Intuitive treatment of math for F-test in multiple regression

Can anyone point to an online explanation of why the F-test works for multiple regression? I found tons online, but I am looking for the sometimes contradictory requirement of the explanation being ...
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### F-test of joint significance vs multiple t-test for regression parameters? [duplicate]

In the context of linear regression, I don't understand why you need to perform an F-test for the H0 that all parameters are zero, instead of just looking at all the t-tests for each parameter. I ...
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### model comparison: chi2 vs. AIC (and BIC)

I've been using the approach from Appendix A from this paper. It states that if I have two fits with $\chi^2$ values $\chi^2_1(\nu_1)$ and $\chi^2_2(\nu_2)$ ($\nu$ - degree of freedom), then their ...
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### Difference between F-test and separate t tests on each variable?

Why can't we separately test each variable(using t-test), whether or not it is equal to 0? Why should we use the F-test for checking if all coefficients combined are equal to 0?
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### Significant omnibus f-test but planned comparison testing showing no evidence of effect

i'm testing the relationship between four age groups of teachers on their perceived level of job security. I've run an omnibus f-test on some data, 240 subjects- no examples of any skewness, and it ...
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### Is F test used for feature selection only for features with numerical and continuous domain?

The F-statistic/test can be used for feature selection, e.g. from http://scikit-learn.org/stable/modules/generated/sklearn.feature_selection.f_classif.html#sklearn.feature_selection.f_classif ANOVA ...
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### How to perform F-test significance testing in Matlab?

I have two quantities in Matlab say T1 (1x44100 array) and T2 (1x44100 array). I have calculated their ratio ...
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### F-Test for Equality of Variances with Weighted Survey Data

I would like to use an F-Test for Equality of Variances on a variable to compare two groups. Normally, this would be done with an sdtest command in Stata or a ...