Introduction

Class A scores: $12$, $14$, $15$, $15$, $90$ Class B scores: $18$, $19$, $20$, $21$, $22$

The mean for Class A is dragged up by one high score. The median tells a fairer story of a “typical” result. Statistics chooses the right summary. Probability then asks: if you pick a pupil at random, how likely are they to have scored above $20$?

Data without summaries is noise. Chance without a sample space is guessing.

You will organise data, compute mean, median, mode and range, read charts, then calculate probabilities, combined events, and tree diagrams.