A biased spinner can only land on one of the numbers 1, 2, 3 or 4. The random variable X X\,X represents the number that the spinner lands on after a single spin and P(X=r)=P(X=r+1)P(X = r) = P(X = r + 1)P(X=r)=P(X=r+1) for r=1,3r = 1, 3r=1,3
Given that P(X=1)=0.16P(X = 1) = 0.16P(X=1)=0.16
show that the complete probability distribution for X X\,X is
| xxx | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| P(X=x)P(X=x)P(X=x) | 0.16 | 0.16 | 0.34 | 0.34 |
Mark spins the spinner 50 times. Show that the probability that the spinner lands on the number 4 more than 20 times is 0.148 to 3 significant figures.
The random variable Y Y\,Y is defined by Y=8−3XY = 8 - 3XY=8−3X. Show that P(Y+X≥1)=0.66P(Y + X \geq 1)=0.66P(Y+X≥1)=0.66
215 exam-style questions on Edexcel A Level Maths Statistical Distributions, covering 6.1 Probability Distributions, 6.2 The Binomial Distribution, and 6.3 Cumulative Probabilities. Each one has a worked solution and a mark scheme showing where the marks go.