Tagged Questions

Hypothesis testing assesses whether data support a given hypothesis rather than being an effect of random fluctuations or some other process described by an alternative hypothesis.

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Hypothesis test of significance using a stratified sample

I am fitting a linear model (OLG) of the form: Y_hat =b0 + b1*x + b2*x*(grp='b') + b3*x*(grp='c') where x=(x1, .., x7) is a vector of continuous predictors, grp is a discrete variable that takes ...
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Any other non-parametric alternative to Kruskal-Wallis?

It looks like Kruskal-Wallis is the standard nonparametric test for more than two groups. The problem is that it does not tell which groups are different, except that whether there exists significant ...
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1answer
15 views

Correlation coefficient significance based on bootstrap distribution

There is data $x$ and $y$ which does not come from two dimensional normal distribution. However I would like to perform correlation coefficient test. For this purpose I have created the bootstrap ...
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1answer
22 views

How to check if people think 3 is a lucky number while we throw with 2 dice

On the marketplace Gypsy accepts bets on two dice throw (he throws two dice at the same time, not one after another). Gamblers come and say what numbers will be on each of the two dice (it is a bet on ...
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A principled method for choosing between t test or non-parametric e.g. Wilcoxon in small samples

Certain hypothesis tests can be approached using Student's t-test, possibly using a Welch correction for unequal variances, or by a non-parametric test such as Wilcoxon paired signed rank test, the ...
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1answer
31 views

How to cope with non-normal ANOVA residuals?

My data follow this outline: ...
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11 views

Use of Chi2 goodness of fit test with three-level nominal variables from two samples

I have two samples. One is comprised of people who did a pre-test but did not do a post-test (n=75). The other is comprised of people who did both the pre- and post-test (n=150). For each sample, I ...
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16 views

How to run a hypothesis test on 3 binary dummy variables?

Consider the following problem: Team A's performance (by month) in Jan-Mar is 200 and in Apr-Dec is 250. Team B's performance (by month) in Jan-Mar is 150 and in Apr-Dec. Furthermore, we know that ...
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8 views

Selecting the right DV in study of treatment effect on a small sample?

I want to run a simple experiment at work to see if making a single change F on a product, has any significant adverse effect on the performance. I need help to ...
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3 views

have two ID with four dimensions and a mediator with two factors and a DV with four dimensions. [on hold]

want to calculate the direct and indirect effects between them. and what kind of techniques should used to analyze data from questionnaire. thanks
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24 views

Determining Appropriate Test: two categorical groups with a goal (split test?) (Newb)

I've spent several hours online researching an appropriate means of using statistics to determine whether or not variation test results are meaningful, or just chance. If the testing took the format ...
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36 views

Confidence interval for differences in total sums

I have data from two variations of an ecommerce web site and would like to determine the confidence interval for the difference in generated profit between the variations. My data contains both the ...
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P value distribution skew & hypothesis testing

On this page it says ...if HA holds, the p-values have a distribution for which values near 0 are more likely than values near 1. However the p-values may have a distribution that is not ...
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1answer
16 views

“Under the ANOVA null, within group and between group sample variance are both estimates of the pop. variance” — why only under the null?

In Statistical Methods by Snedecor and Cochran, it states something to the effect of "the within-group variance is an estimate of overall variance given the null hypothesis" and this point is used to ...
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1answer
31 views

Which statistical test to use with repeated measures & clustered observations?

I am doing an experimental study for my research. I have a class with 24 students and six groups, where each group includes 4 students. I want to compare the performance of each group in two cases: ...
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1answer
72 views

What statistical analysis did they do in this paper?

This is really a beginner question. I have to perform a statistical analysis which is exactly the same as the one conducted in the table shown in the picture. Specifically, how to calcolate the ...
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27 views

Can I say there would be only 2 groups with such features in this data and prove it using cluster analysis?

I assume that there would be two groups that will emerge within the data with my assumed features. I run cluster analysis and best number of cluster (elbow, dendrogram, etc.) shows it will be 2 and ...
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11 views

How to test adjusted mean in R?

I have got eight adjusted means for eight subgroups in a survey study, but I don't know how to test the differences of these eight adjusted means. Any suggestion is appreciated. Thanks!
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1answer
43 views

test interactions for multiple regression with many predictor variables

I have a data set with around 25 predictor variables. If I am planning to build multi-regression model against this data set. What are the general approaches to test the interactions of these ...
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14 views

Help finding critical on a hypothesis contrast

I´ve tried finding the variance using the moment-generating function but apparently that is not the correct method for finding the critical. Can you help me with this?
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8 views

Finding a hypothesis test based on the Neyman-Pearson about a parameter with a piecewise density function

I'm having trouble about how to start this problem. The density function for a random variable $X$ is: $$ f(x|\theta) = \begin{cases} \frac{1}{2(1+x-\theta)^2} & \text{$if x \ge \theta$} \\ ...
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1answer
15 views

Test equality of two measurements for a outcome

I have a binary outcome which were measured with two methods say A and B such a $2\times 2$ table like this: ...
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1answer
29 views

Questions about non-standard test statistic for difference of two population proportions

Background I'm considering the number of observed 'successes' $x_1$ and $x_2$ from $n_1$ and $n_2$ independent trials respectively. These counts can be considered realisations of random variables ...
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33 views

Statistical Test for Two-Alternative Forced Choice Task (2AFC)

I conducted a learning experiment and assessed whether participants learned with a two-alternative forced choice (2AFC) task consisting of 100 items (25 items of category 1, 25 of category 2, items of ...
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1answer
36 views

Number of possible statistical test can be used on the observation data.

I am working on research paper for diagnosis of cancer. List of Known prognostic factors Age of patient Size of tumor Grade of tumor Lymphnode involvement and list of Unknown factors which are ...
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38 views

Test for autocorrelation

I wanted to test if there's significant autocorrelation in my data. Here's the reproducible code(R!) and the result. It looks like that dwtest and bgtest and acf are all too much different. Can ...
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1answer
27 views

Three proportions testing null hypothesis

I have the following question. In a random sample of 250 people with low incomes, 155 are in favour of a new piece of legislation, while in random samples of 200 people with average incomes and 150 ...
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22 views

Chi square test with replicates

Is there anyway to do chi square (or any other ratio rest ) with replicates. For example, my data have measures of different time points, each time points has 4 replicates. The measures are discrete ...
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Distribution of large set of fold changes

My background in stats is limited to a few undergraduate classes. However, I have a question that intuitionally seems to have a statistical answer. Let me describe my intuition first. I do systems ...
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1answer
77 views

Why does a confidence interval including 0 mean the difference is not significant?

Could someone please explain why zero being inside or outside the confidence interval tells you whether or not the difference is significant?
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9 views

Hypothesis Testing with unidentified standard deviation [closed]

A survey found that the average communication of male is 35 and the average communication of female is 65. The data obtained from 100 students from 2 samples and that the standard deviation were _ and ...
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22 views

Is Wilcoxon test still valid if there is some shared information?

I have $N$ samples from a population, and to each sample I apply both method A and method B, recording the time each takes to run ($T_A$ and $T_B$, say) I then define a new pseudo-measurement for ...
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0answers
54 views

Why is permutation test wrong with variance but correct with standard deviation?

I am trying to understand the limits of permutation testing. I wrote up a small permutation test example in R, and found that permutation testing seems to fail when using absolute difference in ...
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0answers
12 views

regarding the statistics to test the impact of some subset values on a given variable

For a given variable, there is a set of values. We know that these values can belong to different clusters. For instance, a lot of values center around a small value while other values center around a ...
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18 views

The way to evaluate the importance of an independent variable in a regression model

In a regression model, like y~( x1, x2, x3). Is there a test or a way to evaluate which independent variable, x1, x2, or x3, is ...
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1answer
17 views

how to evaluate consistency of rankings for n columns

Suppose I have n columns in a matrix (example below has n= 4). Is there a test I can check that the rankings over columns are ...
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1answer
35 views

hypothesis test for a boolean combination of alternatives

I have a student (for a high school project) who has conducted an experiment and collected data in the following (simplified) way: id|situation|scoreX|scoreY ...
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1answer
18 views

Comparison of multiple means using summarized data

I have means, variances, and sample sizes from three geographical sites but not their raw data such that: ...
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2answers
29 views

Is Bonferroni Correction Appropriate for this Analysis?

Suppose I have performed a study wherein I compare a novel intervention (N) against the standard intervention (S). Participants are assigned to N or S randomly, and the study is performed. There are ...
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1answer
24 views

How to present statistical significance results among more than two datasets?

Let us say that we have 5 sets of data: $$ a = (a_1, a_2, \dots, a_{10}) \\ b = (b_1, b_2, \dots, b_{10}) \\ c = (c_1, c_2, \dots, c_{10}) \\ d = (d_1, d_2, \dots, d_{10}) \\ e = (e_1, e_2, \dots, ...
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1answer
125 views

Low sample size: LR vs F - test

Some of you might have read this nice paper: O’Hara RB, Kotze DJ (2010) Do not log-transform count data. Methods in Ecology and Evolution 1:118–122. klick. Currently I am comparing negative binomial ...
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1answer
33 views

What criterion are used to accept/reject hypotheses in ridge regression?

On what basis might one accept/reject a hypothesis when running ridge regression? For example, if I have five predictor variables as part of a ridge regression... what criterion would I use to accept ...
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12 views

comparison of time values as response variable

The data set I have is a 12 subject Latin Square cross-over design with 2 periods (1 or 2), 2 sequences (AB OR BA) and 2 drug formulation treatments (A or B). The subject response variable is a time ...
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12 views

R Cramer Von Mises test

I am using the cramer's test in R using the "cramer" package. There are some options for the kind of Monte-Carlo-bootstrap or eigenvalue (ordinary, permutation and eigenvalue) and the kernel (Cramer, ...
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0answers
37 views

Which statistical test for women height?

Suppose women may have Blue or Red eyes. We make a first cheap research on a 100 women checking just one eye of each woman. So after the research we have results: At least one eye Blue have avg ...
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1answer
34 views

Variance decomposition time series hypothesis testing

I'm doing biological gene expression data. For the genes I analysed, each gene can produce two isoforms, one dominant (Gene isoform 1) one minus can be treated as a by-product (Gene isoform 2). I'm ...
2
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1answer
36 views

Big difference in p-value from permutation test

I have roughly 60 values of discrete temperature satisfaction votes ranging from 0 to 4. In the figure below I have grouped the votes depending on the daily number of hours the individual occupants ...
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1answer
23 views

Confused Beginner Question: Multiple simultaneous tests and signal pollution

The best way for me to explain the problem might be to just give an instance of our data and the type of test/conclusion I am attempting to draw. Unfortunately as the title suggests, my understanding ...
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0answers
9 views

Probability of type ii error of Pareto distribution

We are given the Pareto Distribution is of the form FX(x) = 1 − (1 + x)^(-1/theta) Earlier, it has been derived that the sample minimum from a Pareto function is also Pareto distributed, with ...
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Comparing treatment vs control for ordinal data, controling for potential confounders?

I am new here so bear with me. I have two groups, Intervention and Control. Patients have answered the question: How are your back problems now compared to before treatment? Much better, ...