Probability 2 (Edexcel GCSE Maths): Flashcards

1

Probability that something will NOT happen, given it WILL happen

$P(\text{doesn't happen}) = 1 - P(\text{happens})$

$1 - \frac{1}{6} = \frac{5}{6}$

Set sum of all probabilities equal to 1, then solve

How many times something is expected to happen over multiple trials

Number of trials × Probability

Theoretical average, not exact; actual results may vary slightly

More trials = closer actual results to expected value

Gives results close to what you'd expect

Gives results significantly different from expectation

Larger sample = more confidence about fairness/bias

Write all probabilities and set sum equal to 1

$100 \times 0.5 = 50$