These determine if two variables move together. Pearson’s Correlation measures linear relationships, while the Chi-square test evaluates the independence of categorical variables (e.g., does gender affect voting preference?).
Regardless of which of the 100 tests is used, they almost all follow a unified logic: The assumption that there is no effect or difference. The Alternative Hypothesis ( H1cap H sub 1 ): The claim that there is a significant effect.
The landscape of statistical analysis is defined by a vast toolkit of tests, often cited in the classic compendium 100 Statistical Tests by Gopal K. Kanji. These tests serve as the bridge between raw data and scientific certainty, allowing researchers to determine if their findings represent genuine patterns or mere coincidences. The Categorization of Tests 100 Statistical Tests
Parametric tests (like the t-test or ANOVA ) assume the data follows a specific distribution, usually the normal distribution. Non-parametric tests (like the Mann-Whitney U or Wilcoxon signed-rank ) make fewer assumptions and are used for skewed data or small samples.
The sheer volume of available tests exists because real-world data is messy. You might need a test for circular data (the ), a test for outliers (the Grubbs' test ), or a test for the equality of variances ( Levene's test ). Selecting the wrong test—such as using a parametric test on highly non-normal data—can lead to "Type I errors" (false positives) or "Type II errors" (false negatives). Conclusion These determine if two variables move together
To manage such a large number of procedures, statisticians group them based on the nature of the data and the specific question being asked:
Tests like the Kolmogorov-Smirnov or Shapiro-Wilk check if a dataset fits a theoretical distribution, which is often a prerequisite for more complex modeling. The Logic of Hypothesis Testing The Alternative Hypothesis ( H1cap H sub 1
While the idea of "100 tests" may seem overwhelming, they represent a refined evolution of logic. They ensure that whether a scientist is testing a new life-saving drug or a marketer is testing a website layout, the conclusions drawn are rooted in mathematical probability rather than intuition.