Biostatistics

The Mann-Whitney U Test (also known as the Wilcoxon Rank-Sum Test) is a non-parametric statistical test used to compare two independent groups to determine whether there is a significant difference in their distributions. It is often used as an alternative to the independent samples t-test when the assumption of normality is violated. 1. Introduction 2.…

Correlation is a statistical measure that expresses the extent to which two variables change together. It shows the relationship between two variables, indicating whether an increase in one variable results in an increase or decrease in the other. Types of Correlation Methods for Measuring Correlation Measuring Simple Correlation It measure relationship between two variables only.…

Regression is a statistical technique used to model the relationship between a dependent variable (target) and one or more independent variables (predictors). It helps in understanding how changes in the independent variables affect the dependent variable and is widely used for prediction and forecasting. Types of Regression A. Linear Regression Linear regression models the relationship…

The McNemar test is a statistical test used to analyze paired nominal (categorical) data. It is applied when we have two dependent (paired) samples and want to determine if there is a significant change or difference between the two related conditions. When to Use the McNemar Test? Applications Contingency Table for McNemar Test The test…

This test is used to determine if there are nonrandom associations between two categorical variables in a contingency table usually 2 x 2 tables. It is done when sample sizes are small and the chi-squared test assumptions are violated (expected frequency >= 5). When to Use Fisher’s Exact Test? Steps to Perform Fisher’s Exact Test…

It is the most popular non parametric test of statistical significance for bivariate tabular analysis with a contingency table. This test can be applied to nominal or categorical data, but cannot be used in ranking technique. Conditions to apply \(\chi^2 \) test Conditions to apply \(\chi^2 \) test Formulae \(\chi^2 = \sum \frac{(O – E)^2}{E}…