"post-hoc" refers to analyses that are decided upon after the data has been collected, as opposed to "a priori".

learn more… | top users | synonyms

2
votes
0answers
19 views

Follow up tests for ANOVA and Kruskal-Wallis in MATLAB

For my non-normally distributed data I am using a Kruskal-Wallis test and for normally distributed an ANOVA test. In the MATLAB documentation it just says to use 'multcompare(stats)' function as a ...
1
vote
0answers
73 views

Why does the post-hoc results in R differs the post-hoc results in SPSS?

I have run the same two-way Repeated Measure ANOVA in R and in SPSS. Following that I ran a Fisher's Least Significant Difference (LSD). R script ...
2
votes
1answer
28 views

Is it possible to find non-significant result from one-way ANOVA but significant results from individual post-hoc tests?

I'd like to get some advice on one-way ANOVA analysis with Dunnett's T3 post hoc test. Is it possible to find non-significant result from one-way ANOVA analysis (p=.224), yet find differences in the ...
0
votes
0answers
7 views

post-hoc test for multiple comparisons in a linear mixed effects model with several predictors

I have created linear mixed effects model for a dataset in which I measured bacterial loads (which is logged in the model:log_load) and the the ...
0
votes
0answers
7 views

Retrospective churn test

Is there an appropriate test for the following scenario? A company increases the price of a subscription service. They wish to determine if churn was significantly different after the price change. ...
2
votes
1answer
26 views

Use of post hoc tests following model selection based on AIC

I am working on a dataset of vegetation characteristics recorded over three seasons in two different areas used by buffalo. I have run generalised linear mixed models to determine whether vegetation ...
0
votes
0answers
25 views

inconsistencies in results from global (omnibus) and post-hoc tests in mixed ANOVA

I am running mixed-design ANOVA with one within-subjects repeated measures factor (2 measures), one between-subjects factor (3 categories) and one covariate. Results are following: 1) Significant ...
0
votes
0answers
15 views

Related fixed and random factors in linear mixed-effect models and posthoc tests

I am trying to use mixed-effect modeling to analyze brain wave data from two groups of participants when they were presented with two distinct stimulus. The data points (scalp voltage) were gathered ...
0
votes
0answers
12 views

2x6 repeated measures ANOVA interaction and main effects question

Currently I'm graduating and I'm finishing up my master's thesis as we speak. It's a study about the effect of hand positioning on response time. I'm submitting my data to a 2x6 repeated measures ...
0
votes
1answer
44 views

Conflicting results between GLMM and Post-hoc lsmeans

I'm studying the effect of pH and cross-types on mortality of fish. Treatment is categorical (2 levels: control and low pH) and cross-types is also categorical (4 levels: parents wild male x wild ...
0
votes
0answers
26 views

Dunnett T3 test interpretation

i have result from a Dunnett T3 test using package DTK in R. The result do not give me any p-value but only "Diff", "lower CI" and "upper CI". i can understand the difference between groups as the ...
0
votes
0answers
11 views

Is it possible to test the difference of two regressors in a GLM in matlab?

In matlab, the function fitglm can be used to fit a GLM and test the hypothesis that the weight of a regressor is not zero. However, is it possible to use the result for post hoc multiple comparisons (...
0
votes
0answers
15 views

Test for difference in a set of post hoc tests

I have calibrated an classifier with different sources of training data and I want to evaluate its performance with several data sets. I plan to use the Friedman test and post hoc Nemenyi tests to ...
0
votes
0answers
7 views

Conditional t-test

My question is perhaps on the abstract side: Suppose you plan on performing two t-tests. Test 1 is performed at alpha=0.05. You will only perform test 2 if the results of test 1 are significant. ...
5
votes
3answers
207 views

Does Bonferroni apply to inference from parametric and non-parametric models?

I have run 6 independent-samples t-tests, and 4 Mann Whitney U tests. When applying Bonferroni correction, does it apply across all 10 tests? My hypotheses are that there will be 4 significant ...
0
votes
0answers
3 views

Post-hoc for independent t-tests for a total scale score and subscale scores

I'm comparing two groups on scores on the Dissociative Experiences Scale, and its subscales, using independent-samples t-tests. The DES is a 28 item questionnaire yielding a total DES score. There are ...
0
votes
1answer
40 views

Which R statistics tests to use in order to compare the effects of different variables on a test score

cross posted from StackOverflow I'm hoping someone can help point me in the right direction. I've got a data set which includes 'testscore', 'User Type (a or b)', 'Gender' and 'Age Group'. The data ...
0
votes
0answers
6 views

Tukey HSD for multuple variables and single variable giving different results [duplicate]

I have tried to run Tukey HSD for multi-variable dataset. However, when I run the same test on a single variable, the results are completely opposite. To be more specific: code: ...
0
votes
0answers
26 views

Post hoc test in mixed ANOVA

I use STATISTICA Statsoft to make mixed ANOVAs (module for GLM). I`m not a professional neither in statistics nor in programming, so I may ask not very smart question. The situation is following: I ...
0
votes
0answers
28 views

Understanding Tukey post-hoc Tests for factor variables in GLMs

I performed a GLM, which contained one factor variable (Site), one continuous variable (Days_til_clutch_comp), and an interaction of two factor variables (Host * Egg_type). The levels of Site are: ACT ...
4
votes
1answer
124 views

Which multiple comparison method to use for a lmer model: lsmeans or glht?

I'm analyzing a data set using a mixed effects model with one fixed effect (condition) and two random effects (participant due to the within subject design and pair). The model was generated with the <...
0
votes
0answers
31 views

lsmeans multicomparisons and Fishers LSD

I am using the lsmeans package for "post hoc" multicomparisons and I read here: ANOVA - Do we need a global test before post hoc tests? that in general post hoc tests are valid even if the ANOVA ...
0
votes
0answers
11 views

SPSS Friedman post-hoc - determining best classifier

I'm a newbie, so sorry if the question is too straight forward. I'm comparing 5 algorithms on 10 different data sets. In SPSS I did a Friedman test, and the null hypothesis is rejected. Now I would ...
0
votes
1answer
17 views

Anova and post-hoc's vs CI's

I'm wondering about the use of anova and post-hoc tests versus CI's. If I have a three-way anova design (age group, sex, strain) with n replicates within each cell, the common way to analyze it would ...
0
votes
0answers
13 views

how can I interprets my data if I have a significant difference with an ANOVA but not in the post-hoc results?

I've analyzed the number of contacts that divers of different certification levels have done with the reef and there is a significant difference. When I run the post-hoc test for pairwise comparison, ...
0
votes
0answers
15 views

Chi post-hoc OR Z cell comparisons: do 2 proportion z-tests indicate most significant factors?

Attached is an example of some data I'm working with. I'm testing the occurrence of a rare behavior, while controlling for both education and the "bin" variable. The observed sample size is 129. This ...
0
votes
0answers
39 views

Anova and post hoc test show no significance, but box plot and an unpaired t-test shows differently

I have just preformed a one way anova for 9 treatments and one IV. The p value came back as 0.305. And although it is saying there is no significance I went ahead and did a Tukey post hoc test to see ...
1
vote
0answers
15 views

What is the best approach to test 2 independent groups on 4 DV's?

So I have 1 IV that consists of 2 categorical groups. Both groups complete the same four tasks, the 4 DV's in my study which are continious. I planned a MANOVA, to see whether the DV's are different ...
0
votes
0answers
27 views

ANOVA and post-hoc analysis preconditions

I know that before performing a t-test it's necessary to check if the data are nearly normal and that are not too skewed and also that we can relax the skewness condition as we collect more data. I ...
1
vote
0answers
49 views

R - Post-hoc test on mixed design ANOVA with variable n's

I am attempting to perform post-hoc tests on a mixed-effects ANOVA, and I am running into issues with the typical R-based solutions, which I think stem from the fact that the groups in my between-...
0
votes
0answers
24 views

Factor in linear mixed model is significant, but none of the contrasts?

So I have a linear mixed model with two fixed factors, let's call them A and B, A has three levels (A1,A2,A3) and B two (B1,B2). There is also a random effect, let's call it subject. Over likelihood ...
0
votes
1answer
44 views

Can you use TukeyHSD as a post hoc test for a mixed model?

I completed a mixed model with repeated measures. I did an ANOVA comparing my model to a null model and got a significant value. Now I need to identify where those significant differences are in my ...
0
votes
0answers
25 views

Subgroup differences after group differences analysis

I have two main groups of subjects: no treatment vs treatment. Each group has an equal and large number of subjects. In the treatment group there are 4 subgroups, which have slight differences in how ...
1
vote
0answers
93 views

Post-Hoc test on a Poisson regression

Question How can I perform a post-hoc test after a Poisson regression to know which group differ from which other group? Dummy Data Here are some dummy data (coded in ...
2
votes
2answers
155 views

Post hoc power analysis for a non significant result?

I have submitted a paper to a journal reporting a non-significant finding. One of the reviewers has asked me to include a power analysis on my data to work out how big a sample size I would need to ...
1
vote
1answer
171 views

Interpretting non-contiguous significance letters from Tukey HSD test in the multcomp package? [closed]

I've only ever seen the compact letter display for Tukey's HSD give contiguous letter groupings but like in the following example this package is giving non-contiguous groupings (ie 'cde' is ...
0
votes
0answers
110 views

Interpreting output from lsmeans tukey test

I'm running post-hoc analyses on linear mixed models I ran for a dataset. I'm not totally sure how to interpret the output from lsmeans which is as follows: ...
0
votes
0answers
13 views

How do I manually calculate post-hoc tests of independence between all cells using output from SPSS complex systems module?

I'm trying to run post-hoc tests of independence between all cells using a data set that I need to run the complex samples module in SPSS. How do I use this output that includes population proportion ...
0
votes
0answers
40 views

How to discriminate among different post hoc friedman tests

I had to carry out several Friedman test comparing different yields. I also wanted to conduct a Post-hoc test to distinguish among different systems. I used the R function ...
1
vote
1answer
105 views

Post-hoc tests in mixed model using lsmeans and glht

I have a mixed model with two fixed factors (Insecte and temperature) with two random factors (bloc and date) nested in the temperature treatment. I also include interactions between the fixed factor ...
1
vote
0answers
68 views

What post hoc test should I run for a significant interaction in a two-way unbalanced ANOVA?

I have data with two factors (Category and Treatment) and each factor has two levels (A and <...
0
votes
0answers
72 views

ANOVA with Zero Variance

I have four sites. I would like to run ANOVA with Tukey's HSD post hoc test to show that an average hydrological variable (in this case peak runoff rate) is different across the sites. My issue is ...
1
vote
1answer
89 views

Interpretation of post hoc chi square test results

I have a $2\times 3$ table cross-tabulation. I've done a post-hoc test using SPSS but I don't know how to interpret the results. This is the output:
1
vote
0answers
42 views

Appropriate test for two test groups, one control group and binary outcome

I have the following problem: We send our Clients an email and offer them some new product. Let's say we want to test 2 email designs. Additionally, we need a control group, since some of the clients ...
0
votes
0answers
62 views

Conover and Nemenyi post hoc give different results

Using the Wine tasting data set as provided http://www.r-statistics.com/2010/02/post-hoc-analysis-for-friedmans-test-r-code i did Conover and Nemenyi post-hoc tests. They though give different results:...
0
votes
0answers
48 views

Calculation of pooled variance for mixed effect ANOVA

I have an experiment with 1 within-subject factor, 1 between subject factor and additional factor of blocking (measurements were done in several separated blocks). I have used GLM module of my ...
0
votes
0answers
15 views

How to do a post hoc test on a linear model with interaction?

I am new and I don't have much experience with R. That's why all the previous posts about this topic seem to be too complicated for me to apply for my case. I have ...
0
votes
0answers
41 views

2x2 anova as post hoc test following a 2x3 anova

I did a 3x2 anova - my data looks like in the figure below I get significant main effects and a significant (3x2) interaction. I now want to test the interaction between the blue and green bars. So ...
0
votes
0answers
39 views

Post-hoc tests after within-between Two-Way ANOVA

I'm new here! I have run an experiment with two groups randomized to different experimental conditions (A and B), where an outcome parameter was measured at four time points (1h,2h,3h and 4h) I ran ...
0
votes
0answers
26 views

R: Dunnett's test gives z and t value

I am using R for statistical analysis of my data. For some experiments I have to construct a linear mixed effect model using the lmer function from the lme4 package. For other experiments an ANCOVA ...