1. Does Lavastatin reduce the risk of heart attack? In a Texas Study, researchers gave Lovastatin to 2,325 people, and a inactive substitute to 2,081 people, with an average age of 58. After 5 years, 57 of the lovastatin group suffered a heart attack, compared with 97 for the inactive pill.
The level of significance of the test a = 0.01.
(a) State the null and alternative hypothesis symbolically.
Ho:
H1:
(b) The value of the test statistic is found to be . At , can it be concluded that lovastatin reduces the risk of heart attack? Why or why not? Explain!
2. To test the hypothesis that student who finish exams first get better grades, Professor Hardtack kept track of the order in which papers wer handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation od 96.1, while the last 24 papers handed in showed a mean score of 69.3 with a standard deviation of 24.9.
The level of significance of the test a = 0.05
(a) State the null and alternative hypothesis, symbolically. (0.25 point)
H0:
H1:
(b) State the decision rule: (Region or regions under the sampling distribution of the test, where the null hypothesis will be rejected.) (Note: find the critical value of the test, and state your decision rule)
(a) Compute the test statistic and the p-value
(b) Make decision regarding the null hypothesis,
and then state your conclusion
3. In a bumper test, three cars were deliberitley crashed into a barrier at 5 mph, and the resulting damage in (dollars) was estimated. Five test vehicles of each type were crashed, with the results shown below. Research question: Are the mean crash damages the same for these three vehicles?
Crash Damages ($)
Goliath Varmit Weasel
1,600 1,290 1,090
760 1,400 2,100
880 1,390 1,830
1,950 1,850 1,250
1,220 950 1,920
The level of significance of the test a = 0.05
(a) State the null and alternative hypothesis, symbolically.
H0:
H1:
(b) State the decision rule: (Region or regions under the sampling distribution of the test, where the null hypothesis will be rejected.) (Note: find the critical value of the test, and state your decision rule)
(c) Compute the test statistic. Show the p-value
(d) Make decision regarding the null hypothesis, and then state your conclusion