📊Statistics & Probability

σ

Standard Deviation Calculator

Calculate sample and population standard deviation, variance, mean, and range from any list of numbers. Free online tool.

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Variance Calculator

Calculate sample and population variance from any dataset. Free variance calculator with mean and SD output.

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Z Score Calculator

Calculate z-score from a value, mean, and standard deviation. Free z-score calculator with probability lookup.

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P Value Calculator

Calculate p-value from a z-score or t-score. Free p-value calculator for one-tailed and two-tailed tests.

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Confidence Interval Calculator

Calculate 90%, 95%, 99% confidence intervals for a mean or proportion. Free online CI calculator.

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Margin of Error Calculator

Calculate margin of error for any survey or poll. Free MOE calculator with confidence level options.

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Sample Size Calculator

Calculate the required sample size for any survey or A/B test. Free sample size calculator with power analysis.

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Linear Regression Calculator

Fit a linear regression line to your data. Free regression calculator with slope, intercept, R², and predictions.

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Correlation Calculator (Pearson r)

Calculate Pearson correlation coefficient between two variables. Free correlation calculator with strength interpretation.

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Probability Calculator

Compute binomial probability, single-event probability, and combinations. Free probability calculator for AP Stats and analysts.

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