**Effect of Size Calculator** is an online statistics tool for data analysis particularly programmed to calculate standardized mean difference (d) using means and standard deviations and to calculate the strength of Correlation (r) using equal and unequal groups (d). There are two types of methods used here to perform the error size calculation. The first method uses the input values of Means and Standard deviation and second one uses the inputs of t value and df value to estimate the effect of size

### Definition

In statistics, an effect size is a measure of the strength of the relationship between two variables in a sample based estimate of that quantity that conveys the estimated magnitude of a relationship without making any statement about whether the plain relationship in the data reproduces a true relationship in the population. In this manner, effect sizes complement inferential statistics such as p-values

### Formula for Cohen's d Calculation

Cohen's d is defined as the difference between two means divided by a standard deviation for the data. It can be derived from the formula

### Formula for Pearson r Correlation

The most familiar measure of dependence between two quantities is the **Pearson's correlation**. It is obtained by dividing the covariance of the two variables by the product of their standard deviations. The formula for find out Correlation Coefficient is

The variables of a data set is **very highly correlated** if the correlation coefficients whose magnitude lies between 0.9 and 1.0; **highly correlated** if the correlation coefficients whose magnitude lies between 0.7 and 0.9; **moderately correlated** if the correlation coefficients whose magnitude lies between 0.5 and 0.7; **low correlation** if the correlation coefficients whose magnitude lies between 0.3 and 0.5 and **linear correlation** if the correlation coefficients whose magnitude is less than 0.3. An Effect size measure plays an important role in meta-analysis studies that summarize findings from a specific area of research, and in statistical power analyses

The collection of tools employs the study of methods and procedures used for gathering, organizing, and analyzing data to understand theory of Probability and Statistics. The set of ideas which is intended to offer the way for making scientific implication from such resulting summarized data. To make your Calculations easy, this online Effect of Size Calculator can help you to calculate the standardized mean difference (d) using means and standard deviations and to calculate the strength of Correlation (r) using equal and unequal groups (d)