A poll samples 1,000 of 200,000 voters; the true proportion supporting a candidate is p = 0.55.
Which sampling distribution best describes p̂?
- A
Skewed right with mean 0.55 and SD 0.55.
- Bcheck_circle
Approximately normal with mean 0.55 and SD ≈ 0.0157.
- C
Exactly normal with mean 0.55 and SD 0.5.
- D
Uniform on [0,1].
Explanation
Conditions met. σ_p̂ = √(0.55·0.45/1000) ≈ 0.0157.