Stats 1 - All you need to know

ALL YOU NEED TO KNOW- WJEC STATISTICS 1

PROBABILITY

1. Simple Probability
Remember OR is + AND is ×
n
2. Cr
When 3 are selected from a group containing different types.
Example: If 2 red, 3 blue and 4 yellow, select 3.
2
C1 3 C1 4 C1
P(one…

6. Combination of X
This topic will be the end of a variable or distribution question.
E(X), E(X2) and Var(X) will be given or already found in question.
E(3X-4) = 3E(X) ­ 4 Var(3X-4) = 32Var(X)
E(5-2X) = 5 ­ 2E(X) Var(5-2X) = (-2)2Var(X)
E(6X2 +4X) = 6 E(X2)+4E(X)

7.…