Answer: P(reject H₀ | H₀ is true)

## Explanation The significance level (α) represents the probability of committing a Type I error, which occurs when we reject a true null hypothesis (H₀). **Correct Answer: B** - P(reject H₀ | H₀ is true) - This is the definition of Type I error probability - Significance level = α = P(reject H₀ | H₀ is true) **Why other options are incorrect:** **Option A:** P(reject H₀ | H₀ is false) represents the **power of the test**, which is the probability of correctly rejecting a false null hypothesis. **Option C:** P(not reject H₀ | H₀ is false) represents a **Type II error**, which occurs when we fail to reject a false null hypothesis. **Option D:** P(not reject H₀ | H₀ is true) represents the **confidence level** (1-α), which is the probability of correctly not rejecting a true null hypothesis. In hypothesis testing: - Type I error: Rejecting H₀ when it's actually true - Type II error: Failing to reject H₀ when it's actually false - Power: 1 - P(Type II error) = P(reject H₀ | H₀ is false)

Author: Tanishq Prabhu