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Questions tagged [statistical-test]

A statistical test provides a mechanism for making quantitative decisions about a process or processes.

Statistical Tests

A statistical test provides a mechanism for making quantitative decisions about a process or processes. The intent is to determine whether there is enough evidence to reject a conjecture or hypothesis about the process. The conjecture is called the null hypothesis. Not rejecting may be a good result if we want to continue to act as if we believe the null hypothesis is true. Or it may be a disappointing result, possibly indicating we may not yet have enough data to prove something by rejecting the null hypothesis.

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R: one missing value ruins my Jarque-Bera test

This code does not omit N/As and execute the Jarque-Bera test properly. What code does? I thank you for your advice. library(moments) jarque.test(mydata$item1, na.rm = TRUE) My data structure(list(item1 = c(6, 7, NA, 7, 6, 2, 7, 3, 4, 7, 4, 5, 4,…
Gato
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What is the difference between "t = V1+' ~ '+V2" and "t = V1+' ~ '+V2"? I am getting error "invalid non-printable character U+00A0" with one of it

Trying to work on an Statistical test and below is the code with error. if (data[V1].dtypes == 'float64') or (data[V1].dtypes == 'int64'): if (data[V2].dtypes == 'float64') or (data[V2].dtypes == 'int64'): corre=data[V1].corr(data[V2]) …
Bharath
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Optimal metric for training with Class-specific masked input features and imbalanced dataset

I have a classification problem of 8-classes, which are extremely imbalanced. The input dataset consists of sequences, each of length n features, where n = 19. For each of the 8 classes, I have a prior knowledge which subset of the n features are…
HATEM EL-AZAB
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Pearson correlation test giving NA

I tried to get a Pearson correlation for this data, but it resulted in NA. What goes wrong? My code: correlation <- cor(df$var1, df$var2, method = 'pearson') Data structure(list(var1 = c(2, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, NA, 1, 1,…
Gato
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Spearman-Brown coefficient in R

I have a difficulty in finding a working code example for creating a Spearman-Brown coefficient. I need to do it for a sum variable with two items. I have tried this and others without success. How would you do it? spearman_brown(df, var1, var2,…
Gato
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In what order do one-sided t-tests in R compare two samples?

I want to use t.tests to compare samples of temperatures divided in 2 groups: summer and winter. I suppose that, if any difference is to be detected, it should be in the direction of summer temperatures being greater than winter, therefore I would…
Monelisa
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correlation between 2 sets of variables in a dataframe?

I have 89 variables and 300 observations. I want to have a correlation matrix of 9 variable x 80 variables from my dataset. correlate() has focus() function that gives me the required correlation value but not the p values, Is there another…
Najeha Mohamed
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R: Format dataframe for Mantel-Haenszel test with stratified contingency table

I am studying statistics (using SPSS) with OU but want to learn how to perform tests using R. For dose-response analysis in stratified contingency tables, I want to reproduce using R the linear-by-linear association test of SPSS. I have managed to…
the_gasman
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clinical characterisation p-value calculation

I have 3 groups of cancer patients and I want to check if there are any effect of their clinical data on the results like sex, treatment, or age, which statistical test would be suitable? is it one-way ANOVA? and what would be the fastest way to…
Mimi
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How to interpret test Welch and which tests post hoc should be used after test Welch

I use ANOVA, including the Levene test, unidimensional significance tests, descriptive statistics and the Tukey test. I have some doubts about what happens when the assumption of homogeneity of variance is not met in the Levene test. In many of the…
Anna
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Statistical testing of classifier performance on different populations subsets

I have a dataset of people's medical records which contains people of different races, income levels, genders, etc. I have a binary classification problem, and want to compare the accuracy of the two models: Model 1: I have trained and tested a…
Andrea Russett
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Similarity between coordinates in R

I would like to know if in R, there is a way to see the similarity between two dataframes with coordinates. I have two groups of dates A and B, with the coordinates of sightings of two different species in each one, so, A has longitude and latitude,…
PereSabio
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Best statistical test + code for 4-level nominal predictor and 4-level ordinal outcome

I am trying to decide what the best statistical method to use for my variables, and have considered/conducted logistic regression and chi-square with ORs. Are there any recommended statistical tests for these two types of analyses? Income (high,…
aml129
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Chi-square for 4-level categorical predictor

I am trying to look at the association between Income (high, upper-middle, lower-middle, and lower) and Edition (esci and sci). I have two questions: Can I do a chi-square even though this is not a 2x2 aka the predictor variable Income has 4…
aml129
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Different Cramer's V result on same dataframe when using Shiny package

I am hoping someone can help me. I am performing Cramer's V tests on categorical data in R. Here's an example of the code: #cramer's v df1 <- subset(ACCIDENT_MASTER_single, select = c("SEVERITY", "ATMOSPH_COND")) # Converting into numeric…
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