Hypothesis tests & confidence intervals worksheet with answers

Free printable Hypothesis tests & confidence intervals worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
μ₀x̄c = ?α = 0.01

A machine is set to fill packs with a mean of 100 g; you suspect it underfills. The standard deviation is known to be 3 g. You will weigh a sample of 64 packs and test H₀: μ = 100 against H₁: μ < 100 at α = 0.01. Below which sample mean x̄c will you reject H₀?

μ₀ = 100 gσ = 3 gn = 64α = 0.01
x̄c = g
2.Easy
z −1.9601.96

A machine is supposed to fill bottles with 75 mL on average. The standard deviation is known to be 15 mL. A sample of 25 bottles has a mean of 80.1 mL. Find the test statistic z for H₀: μ = 75.

μ₀ = 75 mLx̄ = 80.1 mLσ = 15 mLn = 25
z =
3.Medium
t −1.99801.998

A sample of 64 students has a mean score of 103.6 and a sample standard deviation of 10. Find the test statistic t for H₀: μ = 100.

μ₀ = 100x̄ = 103.6s = 10n = 64
t =
4.Medium
2.08p = ?

The mean of a population is claimed to be 500; the population standard deviation is known to be 24. A random sample of 36 observations has a mean of 508.32. Test H₀: μ = 500 against H₁: μ > 500. Find the p-value p.

μ₀ = 500σ = 24n = 36x̄ = 508.32H₁: μ > μ₀
p =
5.Hard
μ₀x̄c

A one-sided z test of H₀: μ = 500 against H₁: μ < 500 is done at α = 0.10 with a sample of 100; the standard deviation is known to be 25. In reality the mean is 495.75. Find the power 1 − β of the test in percent.

μ₀ = 500μ = 495.75σ = 25n = 100α = 0.10
1 − β = %
6.Hard
μ₀x̄c

A one-sided z test of H₀: μ = 500 against H₁: μ < 500 is done at α = 0.05 with a sample of 36; the standard deviation is known to be 18. In reality the mean is 493.4. Find the power 1 − β of the test in percent.

μ₀ = 500μ = 493.4σ = 18n = 36α = 0.05
1 − β = %

Answer key

  1. 1. x̄c = 99.13 g
  2. 2. z = 1.7
  3. 3. t = 2.88
  4. 4. p = 0.01876
  5. 5. 1 − β = 66.2 %
  6. 6. 1 − β = 71.06 %

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