Spearman's ρ measures monotonic relationships without assuming normality.
Use Spearman when data is ordinal, has outliers, or doesn't follow a normal distribution.
This calculator is appropriate for any analysis that will be presented, reported, or used to make decisions. Accurate statistical metrics are the foundation of valid conclusions.
Many users interpret statistical results without considering the distribution of the data. Standard deviation is most meaningful for roughly normally distributed data — in highly skewed datasets, the median and IQR are more appropriate measures of centre and spread.
A teacher calculates the class average and standard deviation for an exam: mean 64%, SD 18%. The high SD suggests a wide spread of performance levels — indicating the class may need differentiated support rather than a single revision strategy.
Use Spearman for ordinal data, non-normal distributions, or when outliers are present.