1) An outbreak of food-borne illness was attributed to Salmonella. Epidemiologists determined that the outbreak was caused by ice cream from one company. They sampled 9 production runs and found the level of Salmonella in MPN/g to be:
.593 .142 .329 .691 .231 .793 .519 .392 .418
At Alpha = .01, can we conclude that the average is greater than .3 MPN/g (this level is considered dangerous)?
2) Newsweek reported that 17% of adults attended a musical event in the past year. To test this claim, a researcher surveyed 90 people and found that 22 had attended such an event in the past year. At Alpha = .05, test the claim that this figure is correct.
Stat Assignment 7B
1) The high temperatures for a random sample of 6 days in July are:
85 86 90 77 81 88
At Alpha = .10, is there sufficient evidence to conclude that the standard deviation is less than 10 degrees?
2) The average wind speed in Casper has been found to be 12.7 mph and in Tucson it has been found to be 6.2 mph. To test the relationship between the averages, a sample of 31 days was selected from each city and a summary of the data is:
Casper Tucson
Sample size 31 31
Sample mean 12.85 mph 7.9 mph
Sample standard deviation 3.3 mph 2.8 mph
Is there sufficient evidence, at Alpha = .05, to conclude that the average wind speed is greater in Casper than in Tucson?