## OUTLIER CASES. IDENTIFICATION AND SIGNIFICANCE IN DATA ANALYSIS

By RAFAŁ WAŚKO (Predictive Solutions) In data analysis, it is important to identify unusual observations that are significantly different from the others. Such values, called outliers or outlier cases, can affect the results of statistical analysis and lead to... ## LOGISTIC REGRESSION

By WIKTORIA KORYGA (Predictive Solutions) In practice, the simplest and most commonly used type of regression is the linear regression model, whose parameters are estimated using the Least Squares Method. However, linear regression is only used to predict a continuous... ## GINI INDEX

By WIKTORIA KORYGA (Predictive Solutions) The Gini index is a measure of the concentration of a variable’s distribution. In statistics it is commonly used to describe the concentration (unevenness) of the distribution of a random variable, while its most popular... ## THE POWER OF A TEST

By RAFAŁ WAŚKO (Predictive Solutions) The power of a test is the probability of detecting a statistically significant effect when one actually occurs in the population under study. Without adequate test power, we may make a type II error, meaning that the analyst will... ## SKEWNESS AND KURTOSIS

By WIKTORIA KORYGA (Predictive Solutions) Kurtosis and skewness are measures of asymmetry that describe such properties as the shape and asymmetry of the distribution under analysis. They provide us with information on how the values of the variables deviate when...