All Questions
27 questions
3
votes
1
answer
57
views
Significant results from ANOVA post-hoc Tukey's, insignificant with welch-ANOVA post-hoc Dunnett's T3
I performed one-way ANOVA tests with post-hoc Tukey's to look at multiple comparisons and got highly significant results, but noticed the $F$-value on the ANOVA was high. The SDs in the groups were ...
- 31
1
vote
0
answers
33
views
I'm struggling to find which is the right statistical test to use?
I have two variables: cell death and diet, but on the diet variable I have several groups that I want to compare. I was thinking of doing multiple Mann-Whitney tests, but that would be very time ...
- 11
1
vote
2
answers
489
views
SIgnificant ANOVA but not significant post hoc ... what can I do?
I am analyzing some IHC data on the density of cells in two brain regions(factor 1) in two closely related species(factor 2). My data is composed of an n of 6 for each species and is not normally ...
1
vote
0
answers
66
views
Why is an alpha adjustment not required for factorial ANOVA?
When conducting a 2-way fixed effects ANOVA, there are essentially four null hypothesis statistical tests (NHSTs) that can reasonably conducted with just the ANOVA tables. The first is the omnibus ...
- 6,064
0
votes
2
answers
97
views
ANOVA post-hoc correction question
I am currently analysing data from a recent experiment, in which I will perform a 2 way repeated measures ANOVA (exercise intensity [3 intensities] x time [5 time points]).
I have a significant ...
- 11
1
vote
1
answer
431
views
Upper Bound for Significance level (Equal means where the null would be rejected)
I have been studying Power Analysis and ANOVA and wanted to know how I can find an upper bound for the significance level ($\alpha$), for which $H_0: \mu_1 = \mu_2 = ... = \mu_n$ would be rejected? ...
- 49
4
votes
1
answer
48
views
Is there an optimal way to correct for multiple comparisons where tests depend on the significance of other tests?
Suppose I have a set of tests, represented by their (uncorrected) p-values: $T = \{p_1, \dots,p_m \}$.
These could be, for example, p-values from $m$ ANOVAs, performed on linear regressions with $d$ ...
- 19.5k
0
votes
1
answer
1k
views
How to compare two time-series datasets?
I am trying to compare the financial performance of green bonds and conventional bonds by looking at their historical bond yields, bond prices etc. individually over a certain period of one year. I ...
- 1
0
votes
0
answers
150
views
Kruskal Wallis test gives significance, multiple comparision table doesn't
I'm comparing physico-chemical properties of 8 different kefir samples like viscosity at different storage times. I have 4 viscosity measurements for each group. When I conduct Kruskal Wallis test; ...
- 1
3
votes
0
answers
453
views
Multiple comparisons between two groups (non-parametric)
Update Added more details about the Experimental setup.
My experiment comprised two groups, control (N=25) and experimental (N=26). Each participant belonged to one group. Their performance has been ...
- 123
2
votes
1
answer
3k
views
Is it necessary to do a Bonferroni correction on a) exploratory analysis b) correlations or c) if there are 3 different dependent variables
My study is a 2x2 within design and I have a series of 8 hypotheses. These include one ANOVA , one t-test and 4 Pearson correlations. However, the ANOVA and 3 of the correlations include the same ...
- 61
1
vote
1
answer
1k
views
Generalization of one-sample t-test for multiple groups
If I have some data*, and want to test the hypothesis that it has a given mean $\mu_0$, I know of the possibility of using a one-sample t-test. Here, $\mu_0=0$ could be the null-hypothesis of a ...
- 93
0
votes
1
answer
86
views
Unsure which data to use for ANOVA test
I have determined that a one-way ANOVA test of variances will work best for my data. However, the nature of my data makes me very concerned about making any claims based on significance or not.
My ...
user191541
0
votes
1
answer
91
views
How to interpret results of differences of differences in interactions?
I have a dataset composed of 2 factors of several levels each (i.e. exercise[A-B-C] x muscle [1-2-3-4-5-6]. I'm interested on the effect of the different exercises (A,B,C) on the muscle activation ...
- 11
2
votes
3
answers
1k
views
Should I adjust the significance levels in a multiple (linear) regression with dummy variables, when making many comparisons?
I have an experiment with a continuous dependent variable, and an independent variable with a number of categories, k. The categories come from a randomised controlled trial I ran. There is 1 control ...
- 21
1
vote
1
answer
3k
views
Correcting for multiple comparisons after multiple ANOVAs
I've had to run 5 different ANOVAs (identical 4-way mixed design ANOVAs including the same factors, but on a different dependent variable [a gait parameter] each time). In this case, what would be the ...
- 11
1
vote
0
answers
71
views
Compare statistical significance between 3 main groups and subgroups
I am working on a research paper that is comparing the draft values between 3 main categorical players in baseball - infielders, outfielders, and pitchers, and 2 subcategories - being drafted out of ...
1
vote
0
answers
173
views
Acceptable variance within treatments tested with one way ANOVA
I have six treatment means I am testing (including one control), each with three replicates. I used a Levene's test to verify equal variance, and this did not yield a significant result. My treatment ...
- 13
3
votes
2
answers
481
views
Is Bonferroni correction used for multiple levels, multiple factors, or both?
Bonferroni correction can help us correct our alpha values in multiple statistical testing.
One aspect that I am confused on: Is Bonferroni correction used when we have multiple levels (Does this ...
user46925
3
votes
0
answers
106
views
Difference between one-way ANOVA and all pairwise comparisons with Bonferroni correction [duplicate]
If you have five groups and you wish to know if there is a significant difference between any of the group means, you would have to do 10 pairwise comparisons to test all possible pairs of means. You ...
user46925
6
votes
3
answers
3k
views
Should I adjust p-values when investigating an ANOVA interaction?
I'm conducting an experiment to compare 4 types of headphones. I'm interested in finding out whether the headphones differ in their subjective quality.
Thirty subjects listened to each pair of ...
- 317
2
votes
1
answer
74
views
Is it common practice to correct for multiple comparisons with multiple ANOVAs?
I gave three groups of participants (say groups A, B, and C) different treatments, then gave all groups the same questionnaire. The questionnaire has ~50 questions. I then run ANOVA on each of the ...
- 323
5
votes
1
answer
126
views
What general pattern in the means would produce a non-significant ANOVA result but a positive Tukey?
Why would the results of the ANOVA be non-significant, while a pair-wise comparison using Tukey's Wholly Significant Difference (WSD) is significant? Is their a general pattern in the means of the ...
13
votes
1
answer
1k
views
How much smaller can $p$ values from ANOVA's $F$-test be vs. those from multiple $t$-tests on the same data?
Intro: Having noted the attention received today by this question, "Can ANOVA be significant when none of the pairwise t-tests is?," I thought I might be able to reframe it in an interesting way that ...
- 12.4k
2
votes
1
answer
2k
views
When can we look at the significance of pairwise comparisons rather than an interaction term?
I will defend my Master's thesis on Thursday, and I have a doubt about an analysis that I have to present. In my experiment, I had two independent variables:
Age category (SU = senior unemployed ...
- 33
6
votes
2
answers
20k
views
Multiple t-tests vs. one-way ANOVA
I'm working on a classification problem and I have a very high F1 baseline of 85%. I have trained three classification models and I want to know which one is the best. How can I do so?
I tried two ...
- 205
5
votes
2
answers
13k
views
Test if differences between frequencies is significant
I have the following frequency table:
...
- 1,335