Regression and Correlation

How to use this category

Association pages refuse to jump from r to a cause. The correlation coefficient page stops at r and r squared. The test page adds t and a p-value. The converter needs only a published r and n. Spearman uses ranks. Lines of best fit emphasise residuals and prediction. Linear regression adds inference for the slope. Multiple, quadratic, exponential, and logistic fits are separate because the equation is a different shape and the warnings are different.

Association is a description of pairs until a design says otherwise. Report r when you want the strength and direction. Report a test when you want a p-value from those pairs. Use the converter only when a paper already printed r and n and you cannot see the points. Spearman is the page for ranks and for monotone curves that are not straight. A line of best fit is for the equation and the leftovers. Linear regression is for the uncertainty of the slope. Quadratic and exponential fits are for shapes the straight line cannot earn. Logistic regression is for a yes or no outcome, and it will refuse a list that contains only one of those answers. If the cloud of points has a bend you can see, do not force the straight-line page to agree with you.

The cards above are the whole category, with one sentence on the job each page actually does. Open a page when that sentence matches the decision in front of you. If the sentence is close but the assumption is wrong, read the comparison section on the page before you copy a number into a report, a bid, or a lesson plan.

Worked examples are prefilled so the first result is auditable. Change one input and the ticket updates. The essay under the ticket walks the same arithmetic in sentences, then a second example, then the move that most often breaks the definition. Five questions at the end answer the objections a careful reader raises after seeing the figure. That structure is repeated because the habit of checking is the point, not because the formulas are the same.

Internal links leave this category only when the next formula genuinely lives next door. A standard deviation page may point at variance and at a t test. It should not point at a decking calculator. If you arrived from search on a broad word, use the one-sentence descriptions to discard the near misses. Near misses are how people report a p-value from a test they did not run.

Each worksheet in Regression and Correlation keeps one H1, a canonical URL that matches the tool name, and meta text sized for search snippets. The steps are part of the page, not a hidden modal. If you teach from these pages, project the ticket and the assumptions together so students see the same definition you graded against.

When two tools in Regression and Correlation look alike, read the blurb under each name before you commit. The difference is usually a divisor, a critical value, a waste percent, or a caution that belongs on one page and not the other. That difference is why the URLs stay separate.

Reviewed 21-10-2026. Pages in Regression and Correlation currently include Coefficient of Determination Calculator, Correlation Coefficient Calculator, Covariance Calculator, Exponential Regression Calculator, Line of Best Fit Calculator, Linear Regression Calculator, Logistic Regression Calculator, Multiple Linear Regression Calculator, Pearson R to P-Value Calculator, Pearson's Correlation Test Calculator, Quadratic Regression Calculator, Spearman Correlation Coefficient Calculator.

Every regression and correlation page

• Coefficient of Determination Calculator Turns either a correlation or SSE and SST into r squared and the unexplained share.
• Correlation Coefficient Calculator Reports Pearson r and r squared from paired rows, with a verbal strength band.
• Covariance Calculator Computes the sample covariance of two equal lists and prints both means.
• Exponential Regression Calculator Fits ln y = A + Bx for positive y, then rewrites the curve as y = a e to the Bx.
• Line of Best Fit Calculator Fits y = a + bx, reports residual SSE, and predicts y at a new x.
• Linear Regression Calculator Fits a line and tests the slope with a standard error, t, p-value, and 95 percent interval.
• Logistic Regression Calculator Fits an intercept and a slope to binary 0 or 1 outcomes and counts 0.5-cut matches.
• Multiple Linear Regression Calculator Fits y = b0 + b1 x1 + b2 x2 by least squares and reports R squared.
• Pearson R to P-Value Calculator Converts a published Pearson r and sample size into a two-sided p-value.
• Pearson's Correlation Test Calculator Tests Pearson r with a two-sided t statistic and a decision at 0.05.
• Quadratic Regression Calculator Fits y = a + bx + cx squared and reports the equation and R squared.
• Spearman Correlation Coefficient Calculator Replaces each column with average ranks and reports Pearson r on those ranks.