Topic hub
Descriptive Statistics
Core summaries for describing datasets: mean, median, and mode for center; variance, standard deviation, and range for spread; and skewness for shape.
Frequency Tables: How to Build & Read Them
A frequency table counts how often each value appears in your data. Learn to build one step by step, find relative frequency, and read frequency distributions.
How to Calculate Standard Deviation in Excel
Learn to calculate standard deviation in Excel using STDEV.S and STDEV.P. Step-by-step tutorial, worked example, formula tips, and common mistakes.
How to Find Frequency in Statistics
Learn what frequency in statistics means and how to find class frequency, frequency distributions, and grouped frequency tables with a worked example.
How to Find Outliers: The 1.5×IQR Rule & Formula
Learn how to find outliers using the 1.5×IQR rule. Covers the outlier formula, step-by-step calculation, and a fully worked example with real numbers.
How to Find the Mean: Average Formula and Examples
Learn how to find the mean with the step-by-step average formula. Covers the mean formula, worked examples, and how to calculate average in math.
How to Find the Median: Formula & Steps
Learn how to find the median step by step: sort values, apply the median formula, and handle both odd and even data sets with worked examples.
How to Find the Range in Statistics
Learn how to find the range in statistics: subtract the minimum value from the maximum. Step-by-step examples, formula, and a free range calculator.
Interquartile Range (IQR): Formula & How to Find It
Learn what the interquartile range is, the IQR formula, and how to find it step by step. Includes a worked example, outlier detection, and IQR vs range.
Mean Absolute Deviation & Coefficient of Variation
Learn what mean absolute deviation is, how to calculate it step by step, and how the coefficient of variation lets you compare data sets on any scale.
Mean vs Average - Are They the Same Thing?
Mean vs average — are they the same? In most cases yes, but formally 'average' also covers the median and mode. Learn when they differ and how to use each.
Mean, Median, Mode & Range: The Complete Guide
Learn how to find mean, median, mode, and range with step-by-step examples. Covers what mode means in math, how to calculate each measure, and when to use them.
Median vs Average: What Does Median Mean in Math?
Median vs average explained: learn what median means in math, how to calculate it, and when to use median instead of the mean with clear examples.
Percentiles: Meaning, Definition & How to Calculate
Understand the percentile meaning and definition: the value below which p% of data falls. Covers the formula, a fully worked example, and a free calculator.
Sample Variance Formula: Definition, Equation & Examples
Learn the sample variance formula s² = Σ(xᵢ − x̄)² ÷ (n − 1), step by step. Covers the equation, a fully worked example, and common mistakes to avoid.
Standard Deviation: Meaning, Formula & How to Calculate
Learn what standard deviation means, see the full formula, and follow a worked example to find it for any dataset — sample or population.
The Empirical Rule in Statistics: A 68-95-99.7 Guide
Learn the empirical rule in statistics: 68%, 95%, and 99.7% of normal data fall within 1, 2, and 3 standard deviations of the mean. Worked examples included.
The Standard Deviation Symbol (Sigma): Signs & Notation
Learn the standard deviation symbol: σ for population, s for sample. Understand every sign for standard deviation and which symbol identifies each.
Variance: Definition, Formula & vs Standard Deviation
Variance measures how spread out data values are from the mean. Learn the variance formula and how variance differs from standard deviation.
Weighted Average: Definition, Formula & Calculator
A weighted average gives each value a different importance. Learn the weighted average formula, how to calculate it step by step, and when to use it.
What Is an Average? Mean Definition, Types & Meaning
An average is a single number that represents a set of values. Learn the average definition, mean formula, and when to use mean, median, or mode.