Statistics Calculator
Compute mean, median, mode, range, variance and standard deviation, plus the 95% confidence interval.
Mean (n=8)
5.00
95% CI 3.52 – 6.48 (±1.48)
Median
4.50
Mode
4.00
Range
7.00
Variance
4.57
Std Dev
2.14
Min – Max
2.00 – 9.00
Sample-size hint
Current 95% margin is ±1.48. For a ±1.0 margin you would need n≈18; for ±0.5, n≈71. Halving the margin takes roughly 4× the data.
Sorted: 2, 4, 4, 4, 5, 5, 7, 9
About this Tool
Descriptive statistics summarize any batch of numbers — its center, spread and shape — in a handful of figures. This tool computes mean, median, mode, range, variance and standard deviation from a pasted list, then goes one step further with the 95% confidence interval of the mean. A sample-size hint shows how much data you would need for a tighter margin of error.
Common Use Cases
Grade Exam Scores
Summarize a class set of marks with the average, middle score and spread in one pass.
Read Survey Ratings
Turn 1–10 ratings into a mean with a confidence band instead of a bare average.
Check Experiment Data
Spot noisy measurements fast — a wide range or SD flags readings worth re-taking.
Summarize Any Figures
Sports stats, sales numbers or timings all compress neatly into center plus spread.
Pro Tips
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Sample vs Population
Keep Sample (n-1) when your numbers are a slice of something bigger; use Population only for the complete set.
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Skewed? Trust the Median
A few huge outliers drag the mean up, while the median stays anchored to the typical value.
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Mind the n
Confidence intervals assume roughly 10+ values. With tiny samples the band is wide — collect more data.
FAQs
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