A z test of H₀: μ = μ₀ against H₁: μ ≠ μ₀ gives the test statistic z = 2.22. Find the p-value p.
Hypothesis tests & confidence intervals worksheet with answers
A machine is supposed to fill bottles with 100 mL on average. The standard deviation is known to be 4 mL. A sample of 64 bottles has a mean of 98.9 mL. Find the test statistic z for H₀: μ = 100.
A sample of 25 students has a mean score of 73.2 and a sample standard deviation of 5. Find the test statistic t for H₀: μ = 75.
A sample of 36 students has a mean score of 50.47 and a sample standard deviation of 4. Find the test statistic t for H₀: μ = 50.
In a trial, 50 of 250 patients on treatment A recover, and 14 of 100 patients on treatment B. Using the pooled proportion, find the test statistic z for H₀: p₁ = p₂.
How large must a sample be so that the 90% confidence interval for a mean has a margin of error of at most 0.5? The standard deviation is 5. Find the smallest sample size n.
Answer key
- 1. p = 0.02642
- 2. z = −2.2
- 3. t = −1.8
- 4. t = 0.705
- 5. z = 1.312
- 6. n = 271
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