stat 200 hypothesis testing lab

STAT 200 LAB 6 -Lesson 6: Hypothesis Testing, Part 2Due Tuesday, Oct. 8, 2019
NAME:
Directions
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Answer the questions in this document in a different color and not bolded.
Always show your work; full credit will not be given to answers without work shown. If you do
hand calculations, show your work using the Word Equation editor.
Always clearly identify your final answers and round all answers to 3 decimal places.
For an example of formatting, see the sample lab in the Lesson 1 Module in Canvas.
If you have any questions, post them to the course discussion board.
Use complete sentences and always provide explanations along with any screenshots or
software outputs.
1. A team of researchers has developed a new drug to treat isolated systolic hypertension, also known
as high blood pressure (systolic – top number). They want to know if this new drug lowers the systolic
number. The known side effects of the new drug are headaches and nausea. To address their research
question, they will take a random sample of patients with isolated systolic hypertension to administer
the drug over a 90-day period. Each patient will be examined by an independent physician (i.e., not a
member of the research team) before and after 90 days of using the new drug. The physician will
measure the change in blood pressure during the 90 days. If no change is found, the researchers will
lose their funding for any further research on the new drug.
A. State the null and alternative hypothesis that the researchers should test. Use 𝝁𝒅 to denote
the difference in blood pressure computed as the beginning systolic pressure minus the
ending systolic pressure for each patient.[10 points]
B. What does a Type I error mean in this situation? What are the consequences of making a
Type I error here? [15 points]
C. What does a Type II error mean in this situation? What are the consequences of making a
Type II error here? [15 points]
D. In this scenario, is a Type I or Type II error more serious? Or, are they equally serious?
Explain your reasoning. [10 points]
E. If you were working with this research team, what alpha level would you use? Explain your
reasoning. [10 points]
Assume the researchers complete the study with a sample size of n = 199 who take the new drug and
finds the mean difference is 6.100 with a standard deviation of 25.802. The p-value was .001.
F. Using the alpha level you selected in part E, are their results statistically significant? Explain
why or why not. [10 points]
STAT 200 LAB 6 -Lesson 6: Hypothesis Testing, Part 2
Due Tuesday, Oct. 8, 2019
G. Are their results practically significant? Compute Cohen’s d value and explain why or why
not. [10 points]
H. The 95% confidence interval for the differences in systolic blood pressure is [2.49, 9.71]. If
the alpha for the test was .05, why would this interval confirm that the drug was effective in
the sample? [10 points]
I. Using this scenario, compare and contrast confidence intervals and hypothesis testing. List
at least one similarity and at least one difference. [10 points]