# Tagged Questions

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### Why is “statistically significant” not enough?

I have completed my data analysis and got "statistically significant results" which is consistent with my hypothesis. However, a student in statistics told me this is a premature conclusion. Why? Is ...
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### Statistical problem / explanation [on hold]

A researcher studied the effect of television violence on concentration of a particular blood chemical. In this study, 40 participants were measured over a period of an hour prior to watching a ...
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### How to exclude interaction effect in linear regression modelling?

I am working with biological dataset. I am looking for significantly differentially expressed genes that stand out under effect of 3 different factors (e.x. gut microbiota level has/not, tissue, ...
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### Three important issues

I don't understand three important issues : (1) Why do we calculate the test statistic under the null hypothesis ? (2) Why do we reject the null hypothesis when : p-value < significance level ? ...
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### Relationship between $H_{0}$, $H_{1}$ and the Power of the (one sided) hypothesis test

Suppose we wish to test$H_{0} : p = 0.5$ vs $H_{1} : p = p_{1}$ (where $p_{1} \gt 0.5$ What are the relative difficulties of testing for $p_{1}$ close to $0.5$ or $p_{1}$ far from $0.5$? I know that ...
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### Hypothesis testing inference

Brandon, son of a Dollar store owner, graduated from the Marketing program at York University. He analyses business results in the store and wants to improve the performance of the store. He notices ...
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### Hypothesis testing for multiple distributions

I have a set of distributions (histograms) relating to data sampled from two different populations. Within each population I have $n=15$ distributions. I am looking for a statistical test that will ...
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### Filter insignificant proportions statistically

I have a set of proportions: $(1/10,4/6,1/1,1/1,13/18,3/3,55/57,2/20,416/441,23/29,4/4,...)$. The numerator stands for number of links to some finite group $\{A,B,...\}$, the denominator stands for ...
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### Age Interactions in mixed models

We are using a mixed model to describe trends as subjects age. We have multiple measurements per subject of a continuous outcome. We also adjust for the age at entry into the study. It is of ...
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### How to compare the mean of two samples whose data fits exponential distributions

I have two samples of data, a baseline sample, and a treatment sample. The hypothesis is that the treatment sample has a higher mean than the baseline sample. Both samples are exponential in shape. ...
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### When n increases the t-value increases in a hypothesis test, but the t-table is just the opposite. Why?

The formula for $t$ in a hypothesis test is given by: $$t=\frac{\bar{X}-\mu}{\hat \sigma/\sqrt{n}}.$$ When $n$ increases, the $t$-value increases according to the above formula. But why does ...
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### How to address and acknowledge a significant interaction that has little practical meaning

I am building a model with a highly significant interaction. This interaction was one of our main hypotheses. It is clear, however, that the form that the interaction takes does not represent a ...
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### Combining p-values from different statistical tests applied on the same data

Although the title of the question appears trivial, I would like to explain that it is not that trivial in the sense that it's different from the question of applying the same statistical test in ...
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### When does it make sense to reject/accept an hypothesis?

In To P or not to P: on the evidential nature of P-values and their place in scientic inference, Michael Lew has shown that, at least for the t-test, the one-sided p-value and sample size can be ...
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### Statistical significance in canonical correlation analysis

I do canonical correlation analysis between two multivariate datasets $X$ and $Y$. For each pair of canonical variates (x-y pair) I get the canonical correlation coefficient. How can I test its ...
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### Symmetry of alternative hypotheses of pairwise t-tests with p-value correction?

So I'm using R's pairwise.t.test on 4 populations with a Hochberg p-value correction and an alternative hypothesis that the population on the row has a higher mean ...
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### How to correctly measure effect on heavy-tailed distribution

I ran an experiment on my website where I randomly assigned users to either the treatment or control group, and have two questions about how to correctly compute significance of the results. Some ...
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### Statistically comparing two different cache hit algorithms

I am comparing two different cache hit algorithms using four different training and testing sets. The training sets are related: 1 is a subset of 2 is a subset of 3 is a subset of 4. The same goes for ...
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### one function for three different types

I have the following data sets and results the problem is that I need to create one formula based on the below data but when I create the chart I have three different data ,so as I have no clue on how ...