A machine is supposed to fill bottles with 120 mL on average. The standard deviation is known to be 5 mL. A sample of 100 bottles has a mean of 118.9 mL. Find the test statistic z for H₀: μ = 120.
Hypothesis tests & confidence intervals worksheet with answers
A z test of H₀: μ = μ₀ against H₁: μ > μ₀ gives the test statistic z = 1.61. Find the p-value p.
A sample of 16 students has a mean score of 118.3 and a sample standard deviation of 5. Find the test statistic t for H₀: μ = 120.
The mean of a population is claimed to be 250; the population standard deviation is known to be 24. A random sample of 64 observations has a mean of 243.88. Test H₀: μ = 250 against H₁: μ < 250. Find the p-value p.
A sample of 81 measurements has mean 46.2. The population standard deviation is 15. Find the lower limit L of the 99% confidence interval for the mean.
In a trial, 36 of 120 patients on treatment A recover, and 20 of 120 patients on treatment B. Using the pooled proportion, find the test statistic z for H₀: p₁ = p₂.
Answer key
- 1. z = −2.2
- 2. p = 0.0537
- 3. t = −1.36
- 4. p = 0.02068
- 5. L = 41.91
- 6. z = 2.442
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