A z test of H₀: μ = μ₀ against H₁: μ > μ₀ gives the test statistic z = 1.87. Find the p-value p.
Hypothesis tests & confidence intervals worksheet with answers
A z test of H₀: μ = μ₀ against H₁: μ ≠ μ₀ gives the test statistic z = −2.3. Find the p-value p.
A sample of 25 students has a mean score of 497.9 and a sample standard deviation of 4. Find the test statistic t for H₀: μ = 500.
Two teaching methods are compared. Group 1: 7 students, mean score 88, standard deviation 10. Group 2: 14 students, mean score 76.3, standard deviation 5.5. Assume equal population variances and use the pooled two-sample t test. Find the test statistic t for H₀: μ₁ = μ₂, taking the difference as x̄₁ − x̄₂ (group 1 minus group 2).
A one-sided z test of H₀: μ = 50 against H₁: μ < 50 is done at α = 0.05 with a sample of 100; the standard deviation is known to be 5. In reality the mean is 49.35. Find the probability of a Type II error β in percent.
How large must a sample be so that the 90% confidence interval for a mean has a margin of error of at most 2? The standard deviation is 8. Find the smallest sample size n.
Answer key
- 1. p = 0.03074
- 2. p = 0.02145
- 3. t = −2.625
- 4. t = 3.496
- 5. β = 63.5 %
- 6. n = 44
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