3. A pharmaceutical company is testing a new cold medicine to determine if the drug has side affects. To test the drug, 7 patients are given the drug and 8 patients are given a placebo (sugar pill). The change in pulse rate (beats per minute) after taking the pill was as follows:
Given drug: 
3 
5 
2 
8 
3 
4 
5 

Given placebo: 
2 
3 
4 
1 
2 
1 
2 
4 
Test to determine if the drug raises patients’ pulse rate more than the placebo using α = 0.025
5. The IRS claims that it takes 87.3 minutes to prepare a tax form. You believe it takes longer than 87.3 minutes. You ask 21 tax filers and find the following preparation times:
60, 63, 65, 70, 76, 79, 84, 85, 88, 90, 90, 98, 98, 99, 100, 101, 110, 111, 115, 123, 137
Determine if the preparation time is significantly longer than 87.3 minutes. Use α = .025.
6. Given below are the birth weights of babies born to mothers who took special vitamin supplements while pregnant:
3.23 4.37 3.93 4.33 3.39 3.68 4.68 3.52
3.02 4.29 2.47 4.13 4.47 3.22 3.33 2.64
a. Make a 95% confidence interval for the mean weight of babies whose mothers take vitamin supplements.
b. Do a hypothesis test to determine if these babies weight is more than the mean weight for the population of all babies which is 3.39 kg using α = .025
c. In a short paragraph, describe the relationship between your answer to part (a) and your answer to part (b).
7. A student wanted to study the ages of couples applying for marriage licenses in his county. He studied a sample of 94 marriage licenses and found that in 67 cases the husband was older than the wife. Do the sample data provide evidence that the husband is usually older than the wife among couples applying for marriage licenses in that county? Explain briefly and justify your answer using the methods studied in this course. Use α= 0.05 as the level of significance.
532 
560 
506 
452 
425 
531 
582 
376 
529 
629 
Caffeinated women’s babies weights 
7.5 
6.7 
5.2 
6.8 
7.4 
7.7 
5.6 
6.9 
Noncaffeinated women’s babies weights 
7.8 
7.6 
8.1 
7.5 
7.1 
7.2 
7.9 
Test to determine if the use of caffeine lowered birth weights using α = 0.05.
EXTRA CREDIT: You intend to poll students in order to determine the proportion of all students who will vote in an upcoming election. What sample size do you need to choose to ensure that the margin of error is less than 3% assuming a 99% level of confidence? Hint: “To ensure” means that, even in the worst case scenario which is when the variation is largest, your confidence interval would still have a 99% chance of containing the true proportion of all students.
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