Normal approximation

• 4 steps:

  1. State the 2 conditions : n ≥ 20 p ≈ 0.5
  2. define the distribution N(np, np(1 - p))
  3. Continuity correction - draw number line
  4. Calculate probability using normal CD
• To check if a normal approximation is appropriate:


  • np ≥ 10
  • n(1 - p) ≥ 10