If the underlying populations cannot be assumed to be normal, then by the central limit theorem, the sampling distribution of ₁ - ₂ is approximately normal only if both sample sizes are sufficiently large-that is, when ________. A) n₁ + n₂ = 30 B) n₁ + n₂ ≥ 30 C) n₁ = 30 and n₂ = 30 D) n₁ ≥ 30 and n₂ ≥ 30

Question

Quizplus · Accepted Answer

According to the central limit theorem, the sampling distribution of the difference between two sample means is approximately normal when both sample sizes are sufficiently large (typically, n ≥ 30). Therefore, the best choice is D, where both sample sizes are at least 30.

If the Underlying Populations Cannot Be Assumed to Be Normal