Standard Deviation Calculator for Grouped Data: Frequency-Expanded Midpoints, Mean, Variance, and SD
Use this grouped-data standard deviation helper after converting class intervals to midpoints and expanding each midpoint by its frequency. Built for QC engineers analyzing 20-100 batch SPC readings, instructors summarizing score bands, and analysts moving grouped frequency tables into sample or population SD, variance, mean, standard error, range, z-score, and confidence interval workflows.
12 values
Instant Math
Use when your data represents a subset of a larger population. Applies Bessel's correction.
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Input your numbers into the Standard Deviation Calculator panel to see real-time statistics, variance, and normal distribution charts.