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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Name: ____________________ Date: ____________

1.Easy

A company claims that a proportion of 0.3 of its customers are satisfied. In a random survey of 120 customers, 42 say they are satisfied. Find the test statistic z for H₀: p = 0.3.

p₀ = 0.3n = 120x = 42

z =

2.Easy

A machine is supposed to fill bottles with 50 mL on average. The standard deviation is known to be 4 mL. A sample of 100 bottles has a mean of 49.28 mL. Find the test statistic z for H₀: μ = 50.

μ₀ = 50 mLx̄ = 49.28 mLσ = 4 mLn = 100

z =

3.Medium

A sample of 16 students has a mean score of 37 and a sample standard deviation of 20. Find the test statistic t for H₀: μ = 50.

μ₀ = 50x̄ = 37s = 20n = 16

t =

4.Medium

8 employees take a typing test before and after a training course. For each person the difference d = after − before (words per minute) is recorded. The mean difference is 5.21 and the standard deviation of the differences is 5.9. Find the paired test statistic t for H₀: μ_d = 0.

n = 8d̄ = 5.21s_d = 5.9

t =

5.Hard

In a trial, 16 of 80 patients on treatment A recover, and 38 of 150 patients on treatment B. Using the pooled proportion, find the test statistic z for H₀: p₁ = p₂.

x₁ = 16n₁ = 80x₂ = 38n₂ = 150

z =

6.Hard

In a trial, 72 of 120 patients on treatment A recover, and 144 of 200 patients on treatment B. Using the pooled proportion, find the test statistic z for H₀: p₁ = p₂.

x₁ = 72n₁ = 120x₂ = 144n₂ = 200

z =

Answer key

1. z = 1.195
2. z = −1.8
3. t = −2.6
4. t = 2.498
5. z = −0.9089
6. z = −2.219

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