A survey of 4,581 U.S. households that owned a mobile phone found that 58 percent are satisfied with the coverage of their cellular phone provider. Assuming that this was a random sample, construct a 90 percent confidence interval for the true proportion of satisfied U.S. mobile phone owners.
Answer to relevant QuestionsA "teen ethics poll" was commissioned by Junior Achievement and Deloitte. The survey by Harris Interactive surveyed 787 students aged 1318. (a) Assuming that this was a random sample of all students in this age group, find ...Find a confidence interval for assuming that each sample is from a normal population. a. x-bar = 14, σ = 4, n = 5, 90 percent confidence b. x-bar = 37, σ = 5, n = 15, 99 percent confidence c. x-bar = 121, σ = 15, n = 25, ...An experimental medication is administered to 16 people who suffer from migraines. After an hour, 10 say they feel better. Is the medication effective (i.e., is the percent who feel better greater than 50 percent)? Use α = ...Find the z calc test statistic for each hypothesis test. a. x-bar = 242, μ0 = 230, σ = 18, n = 20 b. x-bar = 3.44, μ0 = 3.50, σ = 0.24, n = 40 c. x-bar = 21.02, μ0 = 20.00, σ = 2.52, n = 30 Procyon Mfg. produces tennis balls. Weights are supposed to be normally distributed with a mean of 2.035 ounces and a standard deviation of 0.002 ounce. A sample of 25 tennis balls shows a mean weight of 2.036 ounces. At α ...
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