Statistics formulas

Add every number in the list, then divide by the count.

Enter Standard deviation and Mean for the Coefficient of Variation Calculator; use finite values in the indicated domain. The calculator reports CV: Coefficient of variation is the relative spread of a distribution. Mean must be nonzero, and CV is most meaningful on a ratio scale with a positive mean.

Enter Sample mean, Sample SD, Sample size, and z (1.96≈95%) for the Confidence Interval Calculator; use Sample size greater than zero and interpret z (1.96≈95%) as a z-score. The calculator reports Margin of error, Lower, and Upper: Approximate CI for a mean with known z and sample SD. The interval uses a z approximation, so small or nonrepresentative samples need extra care.

Pair rows, form sums, then apply Pearson r.

Pair rows, form sums, then solve for slope and intercept.

Mean: sum divided by count.

Compute the z-statistic from the sample mean, hypothesized mean, σ, and n.

Two-tailed p-value from the standard normal tail.

Enter Count below, Count at score, and Total n for the Percentile Rank Calculator; use finite values in the indicated domain. The calculator reports Percentile rank: Approximate percentile rank using counts below and equal to a score. Total n must be positive and at least as large as the supplied counts.

Enter Expected proportion (%), Margin of error (%), and z for the Sample Size Calculator; enter percentage fields as percentage points. The calculator reports Sample size n: n = z² p (1−p) / e² for a proportion. Expected proportion and Margin of error must be entered as percentages, with a positive margin.

Compute the mean, then the root-mean-square deviation.

Subtract the mean and divide by the standard deviation.