What is a hypothesis test?

A hypothesis test is a statistical method used to determine if there is enough evidence to support a specific claim about a population. In hypothesis testing, researchers establish a null hypothesis, which represents a default position or a general statement of no effect or no difference, and an alternative hypothesis, which reflects the presence of an effect or a difference. By analyzing sample data using predetermined statistical techniques, researchers can assess the likelihood that their sample results would occur if the null hypothesis were true.

If the evidence from the sample data is strong enough to suggest that the null hypothesis is unlikely, researchers may reject the null hypothesis in favor of the alternative hypothesis, thereby supporting a specific claim about the population. This process is critical in both scientific research and quality improvement methodologies such as Lean Six Sigma, where data-driven decision-making is emphasized.

The other options refer to different concepts: formulating scientific theories is a broader scientific process not limited to statistical analysis, analyzing survey data may involve various methodologies beyond hypothesis testing, and estimating population parameters is related to statistical inference but does not specifically encompass the testing of hypotheses.