A machine is supposed to fill bottles with 100 mL on average. The standard deviation is known to be 10 mL. A sample of 25 bottles has a mean of 93.8 mL. Find the test statistic z for H₀: μ = 100.
Hypothesis tests & confidence intervals worksheet with answers
1.Easy
μ₀ = 100 mLx̄ = 93.8 mLσ = 10 mLn = 25
z =
2.Easy
A z test of H₀: μ = μ₀ against H₁: μ < μ₀ gives the test statistic z = −2.14. Find the p-value p.
z = −2.14H₁: μ < μ₀
p =
3.Medium
A sample of 81 students has a mean score of 78.78 and a sample standard deviation of 20. Find the test statistic t for H₀: μ = 75.
μ₀ = 75x̄ = 78.78s = 20n = 81
t =
4.Medium
A sample of 100 students has a mean score of 502.6 and a sample standard deviation of 15. Find the test statistic t for H₀: μ = 500.
μ₀ = 500x̄ = 502.6s = 15n = 100
t =
5.Hard
A sample of 100 measurements has mean 98.8. The population standard deviation is 5. Find the upper limit U of the 95% confidence interval for the mean.
x̄ = 98.8σ = 5n = 10095%
U =
6.Hard
In a trial, 35 of 100 patients on treatment A recover, and 92 of 200 patients on treatment B. Using the pooled proportion, find the test statistic z for H₀: p₁ = p₂.
x₁ = 35n₁ = 100x₂ = 92n₂ = 200
z =
Answer key
- 1. z = −3.1
- 2. p = 0.01618
- 3. t = 1.701
- 4. t = 1.733
- 5. U = 99.78
- 6. z = −1.818
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