Educational Attainment and Marriage Age - Testing a Correlation Coefficient's Significance United States Census Bureau | An official website of the United States Government An official website of the United States government Here’s how you know Here’s how you know Official websites use .gov A .gov website belongs to an official government organization in the United States. Secure .gov websites use Topics: Correlation vs. causation Hypothesis testing Line of best fit Linear regression. Topics: Correlation vs. causation Hypothesis testing Line of best fit Linear regression.