A company claims that a proportion of 0.4 of its customers are satisfied. In a random survey of 400 customers, 137 say they are satisfied. Find the test statistic z for H₀: p = 0.4.
Hypothesis tests & confidence intervals worksheet with answers
A z test of H₀: μ = μ₀ against H₁: μ ≠ μ₀ gives the test statistic z = 2.33. Find the p-value p.
A sample of 16 students has a mean score of 209 and a sample standard deviation of 15. Find the test statistic t for H₀: μ = 200.
A sample of 81 students has a mean score of 72.11 and a sample standard deviation of 10. Find the test statistic t for H₀: μ = 75.
In a trial, 50 of 250 patients on treatment A recover, and 44 of 150 patients on treatment B. Using the pooled proportion, find the test statistic z for H₀: p₁ = p₂.
A one-sided z test of H₀: μ = 500 against H₁: μ < 500 is done at α = 0.01 with a sample of 36; the standard deviation is known to be 9. In reality the mean is 497. Find the power 1 − β of the test in percent.
Answer key
- 1. z = −2.347
- 2. p = 0.01981
- 3. t = 2.4
- 4. t = −2.601
- 5. z = −2.131
- 6. 1 − β = 37.22 %
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