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Module 9 Quiz

Test your mastery of two-sample hypothesis testing

Quiz Instructions

15 questions covering all Module 9 concepts
Pass with 70% (11 out of 15 correct)
Instant feedback with detailed explanations
You can retake the quiz as many times as needed

1Which scenario requires a paired t-test?

Comparing average salaries in two different cities
Comparing weight before and after a diet in the same people
Comparing test scores of men vs. women
Comparing heights of two different age groups

2In a two-sample t-test with n₁ = 30 and n₂ = 35, what is the null hypothesis?

H₀: x̄₁ = x̄₂
H₀: μ₁ = μ₂
H₀: μ₁ > μ₂
H₀: p₁ = p₂

3For a paired t-test with 20 pairs of data, what is the degrees of freedom?

20
19
40
39

4In a two-proportion z-test, the pooled proportion p̄ is calculated as:

(p̂₁ + p̂₂) / 2
(x₁ + x₂) / (n₁ + n₂)
(n₁p̂₁ - n₂p̂₂) / (n₁ + n₂)
(p̂₁ × p̂₂) / 2

5A researcher tests if Drug A has a higher cure rate than Drug B. This is a:

Two-tailed test
Right-tailed test
Left-tailed test
Paired test

6In a paired t-test, you calculate differences d = Before - After and get d̄ = 5 with sd = 2 for n = 16. The test statistic is:

t = 2.5
t = 5.0
t = 10.0
t = 20.0

7Which condition is NOT required for a two-sample t-test (independent)?

The two samples must be independent
Both sample sizes must be equal
Both populations should be normally distributed OR both n ≥ 30
Observations within each sample must be independent

8For a two-proportion test with n₁ = 100, p̂₁ = 0.35 and n₂ = 120, p̂₂ = 0.40, the pooled proportion is:

0.375
0.377
0.38
0.05

9A study compares reaction times of 25 people on their dominant vs. non-dominant hand. This requires:

Independent two-sample t-test
Paired t-test
Two-proportion z-test
One-sample t-test

10The main advantage of a paired design over an independent design is:

It's easier to calculate
It requires fewer total observations
It controls for individual variability, increasing power
It always produces significant results

11In a two-proportion test, you get z = 2.5 for a two-tailed test at α = 0.05. What is your decision?

Fail to reject H₀
Reject H₀
Accept H₀
Insufficient information

12Which test uses the z-distribution rather than the t-distribution?

Two-sample t-test for independent means
Paired t-test
Two-proportion z-test
One-sample t-test

13For a 95% confidence interval for μ₁ - μ₂, if the interval is (2.5, 8.3), what can you conclude?

There is no significant difference between μ₁ and μ₂
μ₁ is significantly greater than μ₂
μ₁ is significantly less than μ₂
The test is inconclusive

14A researcher wants to compare average GPAs of students from two universities. She collects independent random samples from each. Which test should she use?

Paired t-test
Independent two-sample t-test
Two-proportion z-test
One-sample t-test

15In a paired t-test, if you calculate d = After - Before and get d̄ = -3.5, this suggests:

"After" values are higher than "Before" values on average
"After" values are lower than "Before" values on average
There is no change
The test is invalid