Casio fx-CG50 field manual for IB Math
39
AI HLPoisson distribution probabilities
Use the Poisson cdf routine to find bounded probabilities P(a≤X≤b).
If X∼Po(4), find P(2≤X≤6).
1
From the MAIN MENU, open Statistics, then press (DIST), (▶), and choose POISSON → Pcd.
2
Press (Var) if Data shows List, then fill in the range directly: Lower = 2, Upper = 6, and μ=4 (the Casio labels the Poisson mean μ).
3
Move down to Execute and press . The calculator prints the probability p on the results screen.
P(2≤X≤6)≈0.798.
Your turn
Work each one on your calculator, then check the answer.
- 1
If X∼Po(5.5), find P(3≤X≤7).
- 2
If X∼Po(3), find P(2≤X≤5).
- 3
If X∼Po(7), find P(5≤X≤9).