Linked Questions

10
votes
2answers
7k views

multiple regression and multiple comparisons

Say I fit a multiple regression of p explanatory variables. The t-test will allow me to check if any single one of those is significant ($H_0: \beta_i = 0$). I can do a partial F-test to check if some ...
335
votes
78answers
158k views

What is your favorite “data analysis” cartoon?

This is one of my favorites: One entry per answer. (This is in the vein of the Stack Overflow question What’s your favorite “programmer” cartoon?.) P.S. Do not hotlink the cartoon without the site's ...
1
vote
1answer
80 views

Why R is not significant (and very low), while all predictors are significant? [duplicate]

I used a network logistic regression to regress five predictors against a dependent. They are all significant, instead the R is not significant and it's even very low. I can understand that it may be ...
3
votes
0answers
17 views

F test fails but t-test does not? [duplicate]

I'm a bit confused about this. I have a model with multiple variables trying to explain the dependent variable. When I use the F test, I don't pass the critical value. But when I seperate the ...
2
votes
1answer
2k views

If the f-test is insignificant but coefficients are significant, can I use it?

If the linear regression's f-test is insignificant but its coefficients are significant in t-test, can I use this regression and its coefficients? In academic journals, I find people use linear ...
1
vote
0answers
83 views

Could removing variables improve model prediction?

Coming from a machine learning background, I have long held the idea -throw in all variables and let regularization and cross validation fight against over-fitting. The reason I am posting this ...
1
vote
0answers
22 views

Why is it possible to get insignificant F statistic (p>0.1) but significant regressor t-tests (p<0.1)? [duplicate]

My results show significant t-tests but an insignificant F-test. Is this possible or are my calculations wrong?
0
votes
0answers
16 views

Can an F-Test be worse than the two single T-Tests? [duplicate]

Normally when conducting an F-Test one is hoping the F-Test of all variables is significant although the single T-Tests yield insignificant results. But can the reverse also be true? That is a worse ...
39
votes
2answers
15k views

Simulation of logistic regression power analysis - designed experiments

This question is in response to an answer given by @Greg Snow in regards to a question I asked concerning power analysis with logistic regression and SAS ...
0
votes
2answers
52 views

Factors a, b and c walk into a regression … (multicollinearity puzzle)

I have three factors a, b, and c. In the three univariate models y ~ a y ~ b y ~ c a and ...
81
votes
0answers
64k views

How can a regression be significant yet all predictors be non-significant? [duplicate]

My multiple regression analysis model has a statistically significant F value however all beta values are statistically non-significant. All the regression assumptions are met. No multicollinearity ...
68
votes
9answers
44k views

Why is it possible to get significant F statistic (p<.001) but non-significant regressor t-tests?

In a multiple linear regression, why is it possible to have a highly significant F statistic (p<.001) but have very high p-values on all the regressor's t tests? In my model, there are 10 ...
14
votes
2answers
9k views

Multiple linear regression for hypothesis testing

I am familiar with using multiple linear regressions to create models of various variables. However, I was curious if regression tests are ever used to do any sort of basic hypothesis testing. If so, ...
2
votes
0answers
56 views

If you know a factor is significant, what is a reason why R might think it's not? [duplicate]

I'm running a logistic regression model where anecdotally I expected age to be a very large factor. If you see from the charts I made in Excel before running the model through R, this is how the ...

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