1. Quiz 7
Hypothesis testing of single samples
z-test and t-test

2. 1. Which of the following pair of statistical hypotheses is NOT valid?
a) H0: μ = 82 kg H1: μ ≠ 82 kg
b) H0: μ ≥ 82 kg H1: μ < 82 kg
c) H0: μ < 82 kg H1: μ > 82 kg
d) H0: μ ≤ 82 kg H1: μ > 82 kg

3. 2. The diagram at bottom is an example of a ________ test.
a) one-tailed, right
b) two-tailed
c) directional
d) one-tailed, left

4. 3. What does a mean? a) probability of a Type I error
b) probability of a Type II error
c) power of a statistical test
d) area in non-critical region

5. 4. Power of a statistical test is defined _______.
a) by 1 — a
b) by b
c) as chance of getting a Type I error
d) as the ability to detect a real difference

6. 5. The z-distribution should be used to test a sample mean when ______.
a) s is known
b) sample size is < 30
c) data are not normally distributed
d) sample size is > 30

7. 6. The t-test for testing a single sample mean may be used when all of the following conditions are true excepting _______.
a) data are approximately normally distributed
b) population SD (s) is known
c) sample size less than 30
d) sample SD (s) is known

8. 7. Given a population with mean 12. 5 seconds and SD of 2
7. Given a population with mean 12.5 seconds and SD of 2.5 s, calculate the test value of a sample of 20 people with a mean of 13.6 s representative of the population? Use a=0.05. a) b)
c) 1.968
d) 1.100

9. 8. A sample of 12 scores has a mean of 25. 0 newtons with SD of 5. 8 N
8. A sample of 12 scores has a mean of 25.0 newtons with SD of 5.8 N. Given a pop. mean of 30.0 N what test value should be use to test whether it is the same as the pop. mean (a=0.05)?
a) 8.37
b) 1.783 c)
d) -5.00