Correlation Coefficient Symbol r

The italic letter r commonly represents a sample Pearson correlation coefficient. Population correlation is commonly written with the Greek letter rho, ρ. For Correlation Coefficient Symbol, r is encoded as U+0072, and its Unicode name is LATIN SMALL LETTER R. Correlation Coefficient Symbol commonly uses italic r for a sample Pearson correlation coefficient. Population correlation is often written ρ, so the report should state which statistic is being presented. Examples include “r = 0.72,” “Correlation r(x,y),” and a correlation matrix whose row and column labels identify the variables. The coefficient should be reported with the sample, method, and relevant uncertainty or significance information required by the analysis. A value of r describes linear association; it does not by itself establish causation. Keep r distinct from r², which is the squared correlation and has a different interpretation. The ordinary letter also appears as radius and other variables, so context is essential. In accessible prose, say “correlation coefficient r” and name the variables rather than relying on the single letter. The encoded character is ordinary lowercase r, U+0072. This page is about statistical notation, not a currency sign or a generic letter lookup. Recopy the sample “Accessible reading: correlation coefficient r,” confirm the final text still contains U+0072, and check that the visible heading names Correlation Coefficient. This final check protects Correlation Coefficient Symbol from font substitution, accidental character loss, and intent drift. r commonly represents a sample correlation coefficient, while ρ often represents a population correlation. Neither letter is exclusive to correlation, so statistical context and any subscripts must be preserved.