US
/ˈstændərd ˌdevɪˈeɪʃən/
UK
/ˈstændəd ˌdevɪˈeɪʃən/
A statistical measure of how spread out data values are from the average.
A small standard deviation means data is tightly clustered around the mean.
Test score standard deviation shows how much students' scores vary from average.
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Standard deviation quantifies variability—essential for understanding data quality. In a normal distribution, about 68% of data falls within one standard deviation of the mean, following the empirical rule.
Essential in quality control, research analysis, and understanding data reliability.
Manufacturing engineers use standard deviation to monitor product consistency.