- Mean body temperature. A formal hypothesis test is to be conducted using the claim that the mean body temperature is equal to 98.6°F.
a) What is the null hypothesis, and how is it denoted?
b) What is the alternative hypothesis, and how is it denoted?
c) What are the possible conclusions that can be made about the null hypothesis?
d) Is it possible to conclude the "there is sufficient evidence to support the claim that the mean body temperature is equal to 98.6°F"?
2.Tax Returns claim: Among those who file tax returns, less than one-half file them through an accountant or other tax professional. A Fellowes survey of 1002 people who file tax returns showd that 48% of them file through an accountant or other tas professional. Find the test statistics.
3.Plane seats. In a 3M Privacy Filters poll, 806 adults were asked to identify their favorite seat when they fly, and 492 of them chose a window seat. Use a 0.01 significance level to test the claim that the majority of adults prefer window seats when they fly.
4.In a KRC Research poll, 1002 adults were asked if they felt vulnerable to identity theft, and 531 of them said "yes." Use a 0.05 significance level to test the claim that the majority of adults feel vulnerable to identity theft.
5.A simple random sample of the weights of 19 green M&Ms has a mean of 0.8635g and a standard deviation of 0.0570g. Use a 0.05 significance level to test the claim that the mean weight of all green M&Ms is equal to 0.8535g, which is the mean weight required so that M&Ms have the weight printed on the package label. Do green M&Ms appear to have weights consistent with the package label?
6.Gun Survey. In a recent Gallup poll, 1003 randomly selected adults in the US were asked if they have a gun in their home, and 37.2% of them answered "yes."
a)What is the number of respondents who answered "yes"?
b)Construct a 95% confidence interval estimate of the percentage of all adults who would answer "yes" when asked if they have a gun in their home.
c)Based on a hypothesis test, can we safely conclude that less than 50% of adults answer "yes"? Why or why not?
d) What is a sensible response to the criticism that the Gallup poll cannot provide good results because the sample size is only 1003 adults selected from a large population of adults in the US?
7.Among 436 workers surveyed in a Gallup poll, 192 said that it was seriously unethical to monitor employee e-mail. Among 121 senior-level managers, 40 said that it was seriously unethical to monitor employee e-mail. Consider that claim that for those saying that monitoring e-mail is seriously unethical, the proportion of workers is the same as the proportion of managers. Identify the test statistics and P-value. If using a 0.01 significance level, what should you conclude about the claim?
8.A simple random sample of front-seat occupants involved in car crashes is obtained. Among 2823 occupants not wearing seat belts, 31 were killed. Among 7765 occupants wearing seat belts, 16 were killed. We want to use a 0.05 significance level to test the claim that seat belts are effective in reducing fatalities.
a) Test the claim using a hypothesis test.
b)Test the claim by constructing an appropriate confidence interval.
c) What does the result suggest about the effectiveness of seat belts?
9. Researchers measured skulls from different time periods in an attempt to determine whether interbreeding of cultures occurred. Results are given below. Using a 0.01 significance level to test the claim that the mean maximal skull breath in 4000 BC is less than the main in A.D. 150.
4000 BC: n=30, mean=131.37mm, and s=5.13mm
A.D. 150: n=12, mean=136.17mm, s=15.62317 mm
a) Test the given using the P-value method;
b) Construct a confidence interval suitable for testing the given claim.
10. Is blood pressure the same for both arms? Listed below are systolic blood pressure measurements (mm hg) taken from the right and left arms of the same woman. Use a 0.01 significance level to test for a difference between the measurements from the two arms. What do you conclude?
Right arm: 102 101 94 79 79
Light arm: 175 169 182 146 144