Mean, Median & Mode Explained
Understand the three measures of central tendency — what they mean, when to use each, and how to calculate them with worked examples.
Range in Statistics
Learn what range measures, how to calculate it, and why it's the simplest measure of spread — plus its limitations in real datasets.
Understanding Quartiles & IQR
A complete guide to Q1, Q2, Q3, and the Interquartile Range — including how to find outliers and interpret box plots.
Standard Deviation Explained
Understand what standard deviation really means, why we square the deviations, and the difference between population and sample formulas.
Variance in Statistics
What variance measures, how it relates to standard deviation, and a step-by-step calculation with a real student dataset.
Z-Score Explained
Learn how to standardise any value, what a z-score tells you about position within a distribution, and how to use it in real exam questions.
Probability Explained
From basic probability to complementary events, union, intersection, and the addition rule — explained with diagrams and worked examples.
Permutation & Combination Explained
Understand when order matters and when it doesn't — with the factorial formula, worked examples, and common exam question patterns.
How to Draw a Histogram
Learn what makes a histogram different from a bar chart, how to choose bin widths using Sturges' rule, and how to read distribution shape.
Scatter Plots & Correlation
How to draw and interpret scatter diagrams, what Pearson r means, and how to draw the line of best fit — with A-Level and IB exam tips.
How to Draw a Pie Chart
Calculate sector angles, draw accurate pie charts by hand, and know when a pie chart is the right choice for your data — and when it isn't.
Line Graphs Explained
When to use line graphs, how to plot them correctly, how to read trends and make predictions — with exam-style questions included.
What Is a CSV File?
Understand the most common data format in the world — how to read comma-separated values and convert CSV data into a clean, readable table.
Data Tables to Graphs
How to take any data table and decide which graph type suits it best — then convert it into a bar, line, or pie chart with correct labels.
Ready to Practice?
Read the theory here, then apply it instantly with our free calculators — step-by-step solutions included.
🧮 Browse All Tools →