How to use statistical tools to test research hypotheses?

Statistical hypothesis testing employs mathematical procedures to determine if sample data provides sufficient evidence to reject a pre-specified null hypothesis (H₀) in favor of an alternative hypothesis (H₁). It is a feasible and fundamental methodology for quantifying evidence against the assumption of no effect or no difference in research. The core principle involves specifying H₀ and H₁ clearly before data collection. Selection of the appropriate statistical tool (e.g., t-test, ANOVA, chi-square test, linear regression) depends critically on the research question, data type (continuous, categorical), distributional assumptions, and sample design. Defining a significance level (α, e.g., 0.05) a priori controls the Type I error risk, and verifying test assumptions (like normality, independence, homoscedasticity) is mandatory for valid results. The resulting p-value indicates the probability of observing the collected data (or more extreme) if H₀ were true. The implementation requires sequential steps: formulating H₀ and H₁, selecting the correct test based on data characteristics, setting α, confirming assumptions are satisfied, executing the test using statistical software (e.g., SPSS, R, Python), and interpreting the outcome (e.g., rejecting H₀ if p-value ≤ α). Applied across disciplines, this structured approach yields objective evidence supporting or refuting research claims, enhancing scientific rigor. The main outputs, p-values and confidence intervals, quantify the strength of evidence and the magnitude of observed effects.