Statistics & Probability / Subcategory
Descriptive Statistics
Descriptive statistics calculators and formulas for measures of spread and central tendency. Covers mean, median, standard deviation, and variance calculations for data analysis.
18Formulas
All levels Difficulty
Updated Oct 2026
← All Statistics & Probability (32) Descriptive Statistics (18)
Fundamental
Harmonic Mean
HM = n / Σ(1/xᵢ)
Fundamental
Geometric Mean
GM = (x1*x2*...*xn)^(1/n)
Fundamental
Weighted Mean
x̄w = Σ(wᵢ*xᵢ) / Σwᵢ
Fundamental
Coefficient of Determination (R²)
R² = 1 - (SS_res / SS_tot)
Fundamental
Pearson Correlation Coefficient
r = Cov(X,Y) / (σX * σY)
Fundamental
Covariance
Cov(X,Y) = Σ(xᵢ-x̄)(yᵢ-ȳ) / n
Fundamental
Skewness (Pearson's Coefficient)
Sk = 3*(x̄ - Median) / s
Fundamental
Percentile Rank
PR = (Number of values below x / Total number of values) * 100
Fundamental
Z-Score
z = (x - μ) / σ
Fundamental
Interquartile Range (IQR)
IQR = Q3 - Q1
Fundamental
Sample Variance
s² = Σ(xᵢ-x̄)² / (n-1)
Fundamental
Population Variance
σ² = Σ(xᵢ-μ)² / N
Fundamental
Range (Statistics)
Range = Max - Min
Fundamental
Median
Median = middle value (sorted data), or average of two middle values
Fundamental
Arithmetic Mean
x̄ = Σx / n
Fundamental
Standard Deviation (Sample)
s = sqrt( sum((xi - x_bar)^2) / (n - 1) )
Fundamental
Coefficient of Variation
CV = σ / μ × 100%
Fundamental
Standard Deviation
σ = √(Σ(xᵢ−μ)² / N)