A pilot study suggests sigma ≈ 5. A researcher wants a 95% CI with margin of error at most 1 unit.
The minimum sample size needed (using z* = 1.96) is approximately:
- A
10
- Bcheck_circle
97
- C
50
- D
25
Explanation
n >= (1.96 * 5/1)^2 = 9.8^2 = 96.04. Round up to 97.