Questions tagged [statistical-test]

a mechanism for making quantitative decisions about a process or processes.

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Statistical test for group membership

suppose I have 2 groups - A and B. From those groups we can draw the distribution (median/mean) etc. and do some statistical tests, such as T-test or Wilcoxon test. Is there any test (similarly, ...
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What statistical test to use when both predictor and response are count data? [duplicate]

I'm running a statistical test on a model that I made in scratch. It involves a bear catching salmon. The predictor variable is how many salmon can the bear eat before it needs to stop for a while and ...
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How to compare two indices with different formulations?

The experiment I am performing requires comparison of a physical property (such as shear modulus $M$) of two regions of a sample (say left and right regions). Smaller the differences, more would be ...
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Hypothesis testing: X impact on Y

I am testing the Hypothesis that: (where Y = life_expectancy and X= GDP) Ho= GDP does not affect life expectancy. HA= GDP affects life expectancy. *I already did the model building and got my ...
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Intervention Study: 2x4 Statistical Analysis and G Power Sample Size Estimation

I am planning an intervention study with the between-subject factor "group" (intervention group vs. active control group) and the inter-subject factor "time" (pre-measurement, post-...
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Can Kruskal-Wallis be used for discrete data?

I have a data frame with variables that are counts, nominal (two groups) and continuous. Two of the continuous variable follow a normal distribution; the counts variables do not follow a normal ...
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What is the time complexity of Shapiro-Wilk normality test?

I am using the Shapiro-Wilk normality test, and I am curious about its time complexity. Here is the formula for $W$: $W = \frac{(\sum_{i=1}^{n}{a_ix_i})^2}{\sum_{i=1}^{n}{(x_i-\overline{x})^2}}$ Let's ...
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Statistical tool to compare different indices

In my research study, I have determined seven indices to measure a physical phenomenon. These indices are derived from different types of rheological tests but all measure the same phenomenon. Of ...
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Appropriate statistical test to use

I am running an experiment where I am testing the difference in effectiveness of constructed wetlands. Essentially, I have a control with unplanted wetlands and treatment with planted wetlands and its ...
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Meauring the differences between groups

There is a metric that counted by different groups. What is the best way to categorize or show the statistical difference between groups? Is ANOVA the best way to evaluate this? The dataset looks like,...
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Regression or statistical test for change in counts after a treatment

I am seeking suggestions for suitable regression or statistical tests to measure the effect of a treatment in counts (or proportions), when a control group is not available. Let's say an event takes ...
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230 views

How to test multicollinearity in Fixed Effects Model in R?

I was using plm package in R and run some pooling and fixed effects model. For ...
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Determining trend statistic for two time series

I have two time series: one with reported scatter plot points, and a solid line that represents a fit to the data based on other variables. Here: https://docs.google.com/document/d/1gizOAV8ZjaATLm-...
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Statistical-Significance of a sample

I have data for 10 subjects. Each subject has 3 trials of a specific test where a muscular tissue is deformed (the last instant of the trial does not correspond necessarly to the highest deformation). ...
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Adequate statistical method to compare objective measure vs estimations

I am using a software for image recognition to do the following: calculate the percentage of a surface that is painted black. On the other hand, there are several observers that estimate the ...
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Merge Confidence and error of statistical tests

Let's say we want to statistically check if a boolean property holds, i.e. we want to know the probability of this property being either 1 or 0. To do so, we run n simulations which represent ...
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How can I use Bayesian statistics to test this particular hypothesis?

There is a set $R=\{r_1, r_2, ..., r_K\}$ of $N$ ranks (where $N>> K$). I test the hypothesis that the ranks in $R$ are not homogeneously distributed in $\{1, 2, ..., N\}$. As I am interested in ...
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Comparison of different statistical tests on different amount of biological replicates

I am testing differentially expressed genes using different statistical tests on different amount of biological replicates (Wilcoxon test, t-test and negative binomial test). Figure below is what I ...
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Statistical test for sample size equals one [duplicate]

I know statistical test usually requires "enough" samples to estimate the uncertainties. But what if I have only one sample in each group, and also I "know" which distribution this ...
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What statistical test should I use to check the difference in a binary variable?

I want to test two different settings of some process which produces an output value based on a parametrized probability distribution (the exact distributions are unknown to me, but they are ...
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Power of Fisher test vs chi squared

Consider an $m \times n$ contingency table and test of independence. Suppose the expected counts are such that chi-squared test is not recommended (close to zero in some cells), as it becomes pretty ...
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Which statistical test to determine if improvement in success rate is due to intervention(s) or chance?

I have a dataset for a few hundred students, some of whom received intervention $A$, some of whom received intervention $B$, some of whom received both $A$ and $B$, and some of whom received neither. ...
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Statistical test to establish that event B is caused by event A

I want to have a statistical test to establish that event B is caused by event A Here event B is customers that are supposed to leaved leave for competitor stay in our company event A is an attractive ...
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Statistical Test to check relationship between Sentence Vectors (1-D Array- Independent Variable) and a continuous numeric Dependent Variable?

Use-Case : Validating the Predictability of "Mean Time to Resolution" from "Text Data" using LSTM What I need to predict (DEPENDENT VARIABLE) : Time to Resolution (Continuous ...
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Relationship between two variables in two groups: a test of correlations coefficients or a WIlcoxon test using ratios?

I would love your opinion on this one. I'll make it quick. I have measures of the volume in two areas of the brain (let's call them X and Y). They are distributed non-normally (I am using ...
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Neyman Pearson Lemma for non-monotonic discrete likelihood function

Let $X \sim f_j, j = 0,1,$ where $$\begin{array}{ c c c } x & 1 & 2 & 3 & 4 & 5 \\ f_0(x) & {1 \over 5} & {1 \over 5} & {1 \over 5} & {1 \over 5} & {1 \over ...
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Transitivity in one sided statistical test

Let's consider 3 samples sets of equal size A,B,C coming from the random variables a,b,c and any consistent hypothesis testing method. If we use A,B to test $H_0: \mu_b - \mu_a = 0\,\,\,\,H_1: \mu_b - ...
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Comparing Proportions - Mix of Small and Large Sample Sizes

I have twenty groups of observations (A1, A2, ... A20), each includes positive and negative cases. I would like to test whether the difference between proportions of positives of each group to others ...
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51 views

Which statistical test do I use?

I am running a study but am unsure which analysis to run. My study involves changing attitudes where participants will be given a questionnaire (on a scale of 1= strongly disagree, 5= strongly agree, ...
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Pick Top 3 - Cochran's Q?

I am trying to determine which statistical test to use. Participants were asked to choose the top 3 most important statements from a set of 15. I have read that Cochran's Q can be used to compare ...
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What statistical test is appropriate? [closed]

I'm running a study that is looking at whether exposure to different conditions can change views. Participants are completing a questionnaire on their views (strongly agree, agree etc.) being exposed ...
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Two tests for the same question

We have two series of scores (continuous variables) obtained for two groups of students formed randomly from a population for which we ask ourselves whether an intervention (a teaching method for ...
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1answer
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Choose proper test for two numerical vectors in different length

I am currently struggling to find the most proper test to serve my needs. The thing is, I have one data matrix. The columns are computational features and each row corresponds to a patient. The last ...
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Chi-squared test, Poisson distribution, type I error overestimated - well-suited test for discrete distributions?

UPDATE I edited my original question to make it as clear as possible. My goal is to find a reliable goodness-of-fit test for Poisson-distributed samples. There are a few discussions here related to ...
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Advice on how to answer the “how large of a sample size do we need to show results” question to non-quant people in a business setting

Not sure if this question is too vague, but I'll give it a shot. I've received many questions from non-quantitative colleagues along the lines of "what sample size do we need to trust these ...
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383 views

How to generate random numbers normally distributed in R or any software with limitations (bounds)?

I am working on a project where I need to generate random numbers for a given task time which is normally distributed with mean = 40, and standard deviation = 150. Because of the high SD, I will get ...
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Why does the value of a conversion rate change the number of observations required when calculating statistical power?

This is probably basic, but I haven't come across it before: With a minimum detectable effect of 10% and a baseline conversion rate of 0.44% it takes 265,857 observations per cohort to reach 80% power ...
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How to test whether different observers are getting the same count result for different species?

I have a set of data with over ten 'observers' and over ten 'species'. The below image is an example of how the data is set out in the table, although I also have it in a three column format of '...
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Working with Discrete-Time Survival Analysis with Random Factors in R

I'm working with some data on artificial (fake) bird nests, looking into their 'survival' from animal attacks. I visited the nests once every two days, for 2 weeks (so my time points are 2,4,8,10,12,...
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Which statistical test for “number of cases” with multiple, different group?

I need your help to identify which statistical test I choose for my data. I am analyzing if the "year of experience" of the nurse at the Triage, may influence the correct assignation of the &...
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How to choose a good test statistic to use in R

I find it hard to understand how to use statistical tests in R. I must use the most compatible statistical test to test if there is a significant difference between the means of 2 samples. I have 2 ...
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How to explain to a non-statistician researcher why the 2-sample Hodges-Lehmann-estimator is reported instead of the difference in median?

I need to explain the result of the wilcox.test in R. Many people believe it's about medians. Of course it is not. I understand this is a useful non-parametric measure about statistical equality of ...
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What is an intuitive way for choosing the right Statistical test?

In my Statistics class, we just talked about Statistical tests. So far I’ve been understanding the material, okay, but now I’m very confused. I get that Statistical tests are used in hypothesis ...