The population standard deviation, symbolized by σ (lowercase Greek letter sigma), measures the spread or variability of a population. Unlike the sample standard deviation (s), which estimates the spread of a sample, σ represents the true spread of the entire population. Its formula is σ = √(Σ(x – μ)²/N), where x is each data point, μ is the population mean, and N is the population size. σ helps determine how far data points typically deviate from the mean and is crucial for making statistical inferences about the population.
