- A researcher is testing a hypothesis of a single mean. The critical z value for α = .05 and a two-tailed test is ±1.96. The calculated test statistic value from sample data is -1.85. The decision made by the researcher based on this information is to ___________

a. reject the null hypothesis

b. fail to reject the null hypothesis

c. redefine the null hypothesis

d. change the alternate hypothesis

- A pharmaceutical company claims that its weight loss drug allows women to lose on average 8.5lb after one month of treatment. If we want to conduct an experiment to determine if the patients are losing less weight than advertised, which of the following hypotheses should be used?
- H0: μ ≤ 8.5; H1: μ > 8.5
- H0: μ ≠ 8.5; H1: μ < 8.5
- H0: μ = 8.5; H1: μ < 8.5
- H0: μ ≠ 8.5; H1: μ > 8.5
- A school counselor randomly selects a sample of 30 students to investigate the impact of a behavior intervention on their academic performance. If she increases her sample size to 50 she will _______ the statistical power of her study.
- increase
- decrease
- not impact

- In general, increasing the alpha level (for example from .01 to .05) will
- increase the likelihood of rejecting the null hypothesis
- decrease the likelihood of rejecting the null hypothesis
- not affect the likelihood of rejecting the null hypothesis