How to Assess Statistical Significance

Statistical significance is a term used to determine whether the results of a statistical analysis are likely to have occurred by chance or whether they are significant enough to be considered meaningful. The process of assessing statistical significance involves comparing the observed data to a null hypothesis and calculating the probability of observing the data if the null hypothesis were true. Here are some steps to assess statistical significance:

1. Define the null hypothesis: The null hypothesis is the default position that there is no significant difference between two or more groups or variables. It is usually denoted as H0.

2. Choose a statistical test: There are different statistical tests depending on the type of data you have, such as t-tests, ANOVA, chi-square, and correlation analysis. The choice of the test depends on the nature of the data and the research question.

3. Calculate the test statistic: The test statistic is a numerical value that summarizes the differences between the observed data and what would be expected under the null hypothesis. It is calculated based on the chosen statistical test.

4. Determine the p-value: The p-value is the probability of observing a test statistic as extreme as, or more extreme than, the one calculated from the observed data, assuming the null hypothesis is true. A smaller p-value suggests that the observed data is unlikely to have occurred by chance.

5. Compare the p-value to the significance level: The significance level, denoted as α, is the threshold for determining whether the results are statistically significant. The commonly used significance level is 0.05, which means that if the p-value is less than 0.05, the results are considered statistically significant.

6. Interpret the results: If the p-value is less than the significance level, then we reject the null hypothesis and conclude that there is a statistically significant difference or relationship between the variables being tested. If the p-value is greater than the significance level, then we fail to reject the null hypothesis and conclude that there is no statistically significant difference or relationship between the variables being tested.

It is important to note that statistical significance does not necessarily mean practical or clinical significance. The interpretation of results should be based on both statistical and practical considerations.