1. In 2006, Merck released a vaccine named Gardasil for HPV - the most common cause of cervical cancer among young women. The company conducted four placebo controlled double blind clinical studies of women aged 16 to 26. The results were
|
Treatment
|
n
|
Cervical cancer cases
|
n
|
Genital wart cases
|
|
Gardasil
|
8487
|
0
|
7897
|
1
|
|
Placebo
|
8460
|
32
|
7899
|
91
|
(a): Give a 99% confidence interval for the differences in the proportion of young women who develop cervical cancer with and without the vaccine.
Lower confidence level:
Upper confidence level:
(b): Give a 99% confidence interval for the differences in the proportion of young women who develop genital warts with and without the vaccine.
Lower confidence level:
Upper confidence level:
Note: your answers should have at least three significant figures.
2. We want to estimate p, the proportion of the population who believes the state of the economy is the most urgent national concern with 99% confidence, and a margin of error no larger than 1%.
How many people need to be surveyed?
Use a critical value with three decimal places of accuracy for this problem!
Sample size: