# Tagged Questions

3answers
59 views

### Basic question regarding n of 1 study. Four weeks intervention

I initially will apologise for any lack of clarity with regards to this question. I'm posing this on behalf of my sibling who is in the biomedical sciences. They have done an intervention on a ...
0answers
23 views

### Estimated marginal means significant, interaction not

This is probably pretty basic question, but how come I can get totally non-significant 3-way interaction, while all the marginal means are significant? See the 3 way interaction in the table.
0answers
13 views

### Repeated Measures of Dependent Randomized Conditions

I'm designing an experiment to evaluate how learnable a software tool is. The basic setup is to have $n$ subjects perform $m$ tasks in a random order, and then test whether the subjects performed ...
2answers
95 views

### What is the most appropriate test for a multi-year different group/yr experiment?

I've been working on a research project for close to five years now. For my thesis I have to show how "well" did my approach improve things. Setup: Every year we use a tool A to brainstorm and ...
1answer
65 views

### ANOVA failed to model data, what is a more appropriate test?

This is a cross-post (http://stackoverflow.com/questions/19432964/anova-error-in-levelsxx) about an error I received in R while trying to run an ANOVA on my data. But error aside, I need help ...
0answers
54 views

### Testing for statistical significance in survey results for different countries

I have just run the same survey on websites in different countries and I want to be able to tell whether there are significant differences between countries. For example if 20% of Germans donate to ...
1answer
100 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 ...
1answer
56 views

### ANOVA with 3 groups- does adding a group close to the mean reduce power?

Sorry for that horrible title. I have run a psychology experiment where participants received one of three sets of instructions (between-subjects). Either they were told to approach the experiment a ...
1answer
59 views

### Significant difference between two variables given a third

Assume I have a number of subjects dividing into three profiles: 1, 2 and 3. For each subject I have recorded two attributes, age and height. First, I want to determine if there is a significant ...
0answers
58 views

### Can I use ANOVA on a small sample size test where only some of the groups are not normally distributed?

I have run an experiment for fertility among fruit fly hybrids. There are six groups that I need to compare for significance with one another. Sample sizes are not equal: the number of trials varies ...
1answer
312 views

### How to report result from two-way repeated measures ANOVA?

I have conducted an empirical study as part of my master thesis. I have developed a software tool where cards can be sorted (affinity diagram) and in the study each test subject did a number of ...
0answers
49 views

### I have a non-signficiant ANOVA for a between subjects variable, but a significant planned comparison, is this allowed?

As the title states, I ran an ANOVA and have a non-significant p for a between subjects variable that I wanted to use pairwise comparisons. I designed the study though with a planned comparison ...
2answers
415 views

### How can you implement a two-way ANOVA with nesting in R or SPSS?

I currently am conducting a study where I have three variables: one that is binary, and two numerical ratio variables. Each of the subjects in my study has values for each of the three variables. ...
2answers
895 views

### What does a significant intercept mean in ANOVA?

Consider a model with a continuous response variable and a categorical explanatory variable. I appreciate that in R, a summary.lm output of an anova on this data gives you rows that represent the ...
0answers
54 views

### Which repeated measure statistical test must I use in this case?

I have a set of general conditions A, B, C, D, E and F to solve a problem. Each of these conditions lead me to different number of experiments according to a parameter that i change in each general ...
1answer
108 views

### Reduced models after finding significant interactions

If you run an ANOVA and find that there are significant interactions, do you then pull the variables out individually and re-run the ANOVA? I am using Type III. I want to see if there is a ...
2answers
303 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 ...
1answer
39 views

### Insignificant block effect in two-way block design

I used a two-way ANOVA to analyze data collected in a randomized complete block design: Y~Treatment+Block, where blocks represented spatial units Whereas Treatment had a significant effect on Y, ...
1answer
73 views

### Simple Mixed Model with 1 Fixed and 1 Random Effect

I have various datasets I need to analyse regarding soil properties, all in the same fashion, with one fixed effect (which is a position along a transect, indicating different land uses). Now my main ...
1answer
762 views

### Two-way anova with interaction term: what is the point of a post-hoc test?

I have a statistics interpretation question. I've recently performed a two-way anova to identify an interaction term between my categorical independent variables (genotype + temperature) that ...
1answer
45 views

### How to prove the number of distinct distributions in a group of distributions?

Let's say we had 5 distributions: A,B,C,D,E. An ANOVA test would tell us whether or not all of the means are equal, and thus a low p-value would mean at least one of the means is unlikely to be ...
0answers
44 views

### What kind of statistical analysis to use for a homework paper? Anova?

I am writing a paper where I have to pretend to have conducted an experiment. Each of the experimental groups and control has different people. There are 8 experimental groups and 1 control. 1a 1b ...
0answers
64 views

### Calculating differences between groups and across time (age)

Let's say I have data of one variable $V$ measured for two groups of individuals ($a$ and $b$) and I want to see whether there is a significant difference between them and over time, i.e. $V_a$ stays ...
0answers
88 views

### Expected value of sums of squares of a blocking factor in a split plot design

How can we show that in a split plot design, the expected value of the sum-of-squares of the blocking factor has expected value equal to $k\sigma^2_{\text{block}} + \sigma^2_{\text{error}}$? I tried ...
1answer
213 views

### How to interpret a non significant independent variable?

I conducted a regression analysis using R's lm() function. One of the independent variables shows no significance (p = 0.89), which contradicts the hypothesis that is should have a significantly ...
1answer
39 views

### Validation for ANOVA question

Can someone help me validate my answer to this question: My answers come from the first row, where the significances are 0.0002,0.0011, and 0.0005, respectively. Since they are all below 5%, then ...
1answer
88 views

### Testing for differences, would I use ANOVA?

I have four age groups all measuring different heights: How would I test for difference between the groups at 0.01 level of significance? Would I use ANOVA? Also - how could I establish which group ...
0answers
135 views

### Can I trust the result of a one-way ANOVA with many treatments each with very few replicates

I am doing a one-way ANOVA of a response variable (Y) on a treatment factor (T) of 7 levels. However, for each treatment, I have only 2 observations (or replicates). The ANOVA result shows the the ...
1answer
118 views

### Comparing means of three groups

When I want to compare the means between two groups I use a t-test. But how do I check whether the means of three groups are equal or statistically different? E.g. compare the average labour ...
0answers
46 views

### How to estimate the out crosses rate in crops?

How to estimate the out crosses rate in crops? in have experiment included; main plot (1- seeds from open field 2- seeds from free pollinators cage 3-seeds from pollinator cage), sub plot (5 ...
0answers
131 views

### Estimating comparative success of different brochures

The Real World Problem One of my clients is preparing to send a direct mailer to their subscribed user list, and this statistical challenge came up. Their marketing team has 3 different brochures, ...
1answer
63 views

### Scientific way to show significance / test hypothesis

I am writing a report to show my results where, if there are more than 3 consecutive English character in a term, that term is noise. For example, "wooooh", "Noooo", etc. I have collected 100 sample ...
2answers
645 views

### Analysis of variance not statistically significant… but is there still a pattern to the data?

Problem I have a computer algorithm, and am attempting to measure the affect of a parameter (NS) on the output of the algorithm (SC). My hypothesis is that if the level of NS is lowered, there should ...
0answers
183 views

### Comparing the results of one-way-ANOVA and two-way-ANOVA

I don't know how to interpret the results of my one-way-ANOVA and two-way-ANOVA. I have 2 independent variables (s.b.'s trust in the internet="v_563" and internet usage(frequency) = "v_614"). I ...
2answers
913 views

### Anova repeated measures is significant, but all the multiple comparisons with Bonferroni correction are not?

I counducted a mixed model ANOVA with time as the within subjects variable (3 levels) and group as the between subjects variable (2 levels). All is significant (time, group, and timeXgroup). To test ...
1answer
108 views

### Can lack of main effect and lack of interaction be caused by the same confound?

Can the lack of main effect have the same underlying cause as the lack of interaction in 2-way ANOVA? My results failed to reach significance for variables of gender and language. Is it possible that ...
1answer
511 views

### What does it mean to have an F-value of .000 and Sig. of 1.000 (in SPSS)?

We conducted this very simple 2x2 Between Subjects Factorial Design Experiment, where the DV were their answers to a classic insight problem. Since there is only one correct answer to the problem, the ...
0answers
226 views

### Unfold degrees of freedom of interaction in factorial design analysis in R

I've been trying to analyse data from a factorial design with missing cells without much success until now. I'm using Anova from car package, that, according with I've read, can handle unbalanced data ...
1answer
228 views

### Using ANOVA and t-tests with pre-aggregated data

I have a set of experiments that I'd like to run some significance tests over. It looks like: ...
0answers
451 views

### How can I compare the effect of an pre-post intervention between two groups with multiple numeric dependent variables?

I have collected data from two groups (age 25-30, age 30+). In each group I have 10 patients. I performed several medical tests (i.e., R.B.C, Liver test, etc.) on the patients, before and after ...
2answers
4k views

### What if an overall ANOVA is not significant, but specific contrasts are?

Study Design: I have a 2x3 factorial design, 2 levels of Time (2050 or 2100) by 3 levels of information (None/Control, Moderate, Extreme). I set up some very specific contrasts when analyzing this ...
2answers
1k views

### Statistical Significant Difference between 5 groups of data

I'm trying to compare 5 different gears used by fishermen and the amount of bycatch found in each. The values have a unit of "% of time encountered" and range between 0% (ie: never have bycatch) and ...
1answer
2k views

### What statistics should I use to compare percentages?

I am trying to see if there is a statistical significant difference between the amount of bycatch in 5 different types of gear used by fishermen. For each gear I have varying number of replicates as ...
0answers
46 views

### Can two RM ANOVAs be run including one variable that is the same but this variable only be significant in one of the ANOVAs? [duplicate]

Possible Duplicate: Why ANOVA/Regression results change when controlling for another variable I have used SPSS to run two RM two-way ANOVA with the same data. RM ANOVA #1 has two within ...
1answer
868 views

### ANOVA in SAS: Not Statistically Significant but LSMEANS says is?

I'm running an ANOVA model. I found my model does not meet constant variance assumption and corrected for that using a weighted ANOVA model. I don't think that changes anything.. After I run the ...
1answer
526 views

### Is it permissible to run post-hoc tests after a non-significant ANOVA?

We ran a 3-way ANOVA getting a non-significant result, but in doing so we saw that one condition looked like it had a strong effect. We tried a Bonferroni-corrected t-test of just that group, and it ...
1answer
62k views

### How to interpret and report eta squared / partial eta squared in statistically significant and non-significant analyses?

I have data that has eta squared values and partial eta squared values calculated as a measure of effect size for group mean differences. What is the difference between eta squared and partial eta ...
2answers
341 views

### Is significance more important than absolute value?

I have three groups and I'm comparing two graphs in each group using the t-test: the absolute difference between two graphs in the first group is 34 with a p=0.024. (*) The absolute difference in the ...
2answers
3k views

### Do we need a global test before post hoc tests?

I often hear that post hoc tests after an ANOVA can only be used if the ANOVA itself was significant. However, post hoc tests adjust p values to keep the global type I error rate at 5%, don't they? So ...
1answer
3k views

### Which non-parametric test can I use to identify significant interactions of independent variables?

I have an experiment producing results (dependent variables) that don't pass tests of normality, thus I am testing hypotheses using non-parametric tests. My DVs are continuous, while my factors ...