Statistics: Testing hypotheses
6:21 .. LTE + H learnuseast'Iprodf|eet02xythos.content.blackboardcdn.c0m 8) A news station reports that 60% of the people in a certain community are in favor of requiring masks to be warn when residents are not In their homes. A survey is conducted to verify this claim and found that 25 out of 44 people surveyed agreed that masks should be warn when people are out in public. Test the claim at an alpha of 0. 10. 9) If our conclusion in problem #8 is actually incorrect due to sampling error. Would this be a Type I or Type II error? 10) If our conclusion in problem #4 is actually incorrect due to faulty sampling or calculations, What type of error would this be (Type I or Type 1])? 11) Give a situation where a Type I error would be a good thing. 12) Give a situation where a Type I error would be a bad thing. 13) The average age of 20 femaie students is 21 with a standard deviation of 3.5. The average age of 26 male students is 21 with a standard deviation of 1.5. At an alpha of 0.05, is there a difference in the ages of these two groups? 14) The Celtics are averaging 95 points per game with a standard deviation of 10. The Lakers are averaging 98 points per game with a standard deviation of 7. Test the hypothesis at a 0.05 level that the Lakers offense if better than the Celtics. Given that they both have played 38 games. 15) It is claimed that Bridgeton tires last at least as tong as Micheline tires. A customer believes that they (Bridgeton's) actually last less than Micheline's. A survey of 49 Bridgeton's showed a mean life of 52,000 miles with a standard deviation of 10,000 miles. 49 Micheline tires had a mean life of 53,000 miles with a standard deviation of 7,500 miles. Test the hypotheses at a 0.05 level. 16] 20 Freshman and 20 Seniors were surveyed to see if they prefer online classes to F2F classes. 1] Freshman and 9 Seniors preferred online classes. These the hypotheses at a 0.10 level that that is no difference between the preference of Freshman vs Seniors. 17) If is hypothesized that females feel less safe on campus when walking alone aer dark than do males. To test this hypothesis, 36 females and 36 males were surveyed. 20 females indicated that they don't feel safe after dark and 16 males indicated that they feel less safe aer dark. Test the hypotheses at a 0.05 level. 6:21 ..| LTE + H learnuseast'Iprodf|eet02thhos.content.blackboardcdn.com 1) It is stated that the average age of college freshman is 19 and the standard deviation of the population is 0.8. A sample of 36 freshmen has a mean age of 18.2 . Test the hypothesis that the stated value is not signicantly different than the sample at an alpha of .05 2) The mean IQ score is 100 with a population standard deviation of 15. Test the hypothesis that New Hampshire residents have a different 1Q. A group of 49 NH residents surveyed at random have a mean 10 of 108. Use alpha = .05 3) John claims that he can throw a baseball 85 mph. We think that John is exaggerating. Test the claim at .05 signicance if a sample of25 pitches shows an average velocity of 82 mph with a sample standard deviation of 2.6. 4) A tire manufacturer advertises that their tires last 40,000 miles. A customer questions the claim as being overstated, and does a survey of 100 tires and nds the mean life to be 36,000 with a standard deviation of 3,500 miles. Test the hypotheses at a 0.10 level. 5) A company advertises that their starting salary for new workers is $50,000. It is known that the population standard deviation is $8500. A sample of 36 new workers have a mean salary of $52,000. Test the hypothesis at an alpha of .05. 6) An instructor claims that the average number of hours needed to study for a nal exam in order to pass should be 5 hours. A student believes that the instructor is understating the number of hours needed to pass and surveys 36 students and nds the sample mean and standard deviation to be 5.7 and [.5 hours respectively. Test the instructors claim at a 0.10 level. 7) A parent claims that children spend about 2 hours a day in front of computer screens. We think that the parent is underestimating the situation and do a survey 0125 children and nds a mean of 3.5 and sample standard deviation of 1.2 hours. Check the parents claim at the .05 level. 8) A news station reports that 60% of the people in a certain community are in favor of requiring masks to be warn when residents are not In their homes. A survey is conducted to verify this claim and found that 25 out of44 people surveyed agreed that masks should be warn when people new alpha of 0.10
