# Tagged Questions

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### Is there such a thing as a matched-pairs t-test between two lists of proportions?

I am aware that there is a matched-pairs t-test between two lists of counts. However, I cannot find any matched-pairs t-test of proportions. For example, list a may be [1/2, 24/30, 5/8] and list b may ...
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### How to test whether variables are more frequently associated than expected by chance?

I have this presence/absence matrix (S2 is missing on purpose). ...
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### Some questions about comparing correlation coefficients

I am working with a dataset of about 1000 objects. I am trying to create models to predict some property of the objects. I am using different factors to describe objects which give me different number ...
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### Unexpected correlation, Method to account for the shared variance

Summary: While looking at the correlations I noticed a wired, relation. Variables: User comments - A; User community activity- B; Comments on user's wall - C (control) I expected that A and B will ...
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### Measuring statistical significance using correlation of ranked (ordinal) data

I am trying to do hypothesis testing and am wondering if I am setting up this problem correctly: My hypothesis is that the reviews of the computer parts for a computer model 'M' on website A ...
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### Measuring correlation or dependence between two data sets

Is there any statistical test or measure to evaluation the degree of correlation or dependence between two sets of data-points ?
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### How to test for a monotonic relationship between two variables, without assuming a specific functional model?

I'd like to test the hypothesis that there is a monotonic relationship between two variables, without assuming a specific model. What is the most robust (i.e. lowest probability of type-II error) way ...
548 views

### Significant regression coefficients but non-significant bivariate correlations [duplicate]

Possible Duplicate: How can adding a 2nd IV make the 1st IV significant? For two of my main variables, the bivariate correlation coefficients (with the outcome measure) are non-significant ...
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### How do you choose the timeframe for a prediction to be tested?

To (hopefully) clarify the question a bit more if you have a broad working hypothesis that x influences y, on a causal/predictive basis (e.g. if x goes up in time t, then you would expect y to go up ...
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I am looking at the probability of opting into a program based on a continuous variables $X_1$, $X_2$, $X_3$, etc. When I divide the sample into people who opted in and did not opt in and do a t-test ...
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### Increase sample size for significant correlation

At the moment I have $5$ paired samples for correlation. Spearman's R is $0.2$ and the $p = 0.78$. How do I calculate the number to extra samples I would need to get a more significant p-value?
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### Analysing choices pattern

we have a process in which, at each step, a set of elements are presented to user, the user choses one, his choice is recorded and next round starts with a new set of elements. For example: 1. ...
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### Calculating statistical significance between dependent Spearman coefficients

I have a set of scores on a specific dataset given by human evaluators, let's call it HJ. I also have the scores of two computer models on the same dataset, let's ...
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### Are observations consistent with each other?

I have 60 apps. For each app, I look at 10 review of that app, and count how many of the reviews say the app is unreliable. Let $X_i$ denote the number of such reviews, for the $i$th app. I want to ...
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### P values seem to be the wrong way around

Say the null hypothesis is that two samples emanate from two distributions with either equal medians or equal variances. And p values are the probability that a value or more extreme comes from the ...
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### Multivariate correlation in sensitivity analysis

I have a vector of parameters $\theta=(n,ph,pt,\gamma)$ which are fed into a process which produces a result. I would like to quantitatively report the sensitivity of the result to the variation of a ...
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### Akaike Information Criterion and composite variables

Akaike information criterion is a measure for goodness of fit of a model that compensates for the number of parameters that were used to build that model. Consider two linear models, one that is ...
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### Example of strong correlation coefficient with a high p value

I was wondering, is it possible to have a very strong correlation coefficient (say .9 or higher), with a high p value (say .25 or higher)? Here's an example of a low correlation coefficient, with a ...
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### Chi square based measure for fairness?

I have some project categories $(PC_1, ... ,PC_n)$ and some institutions $(I_1, ..., I_n)$ and would like to determine how fairly projects are assigned to institutions and their project categories by ...
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### Can we compare correlations between groups by comparing regression slopes?

In this question they ask how to compare Pearson r for two independent groups (such as males vs females). Reply and comments suggested two ways: Use Fisher's well-known formula using ...
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### How do I compare correlation coefficients of the same variables across different groups?

I am testing the correlation between Variable A and Variable B by gender and marital status. So I have the coefficients for males and females and single, married and other. I want to compare the ...
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### Changing null hypothesis in linear regression

I have some data that is highly correlated. If I run a linear regression I get a regression line with a slope close to one (= 0.93). What I'd like to do is test if this slope is significantly ...
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### What test to compare community composition?

Hope this newbie question is the right question for this site: Suppose I would like to compare the composition of ecological communities at two sites A, B. I know all three sites have dogs, cats, ...
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### Hypothesis test for whether correlation coefficient is greater than specified value?

I want to test whether a correlation coefficient is greater than 0.5. What should the null and alternative hypothesis be? Should I do a two tailed test or one tailed test? Thanks
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### Construct probability that measurement belongs to one of two sets

We are dealing with a measurement apparatus that is cursed by noise and are trying to find out if a measurement was noise or an actual measurement. Assume we have a beam of light incident on an ...
I have searched a lot, and I can only find tables that show critical values up to n=30. Can someone provide, or point me to, a simple method of estimating this value for different $\alpha$?