A car dealer wants to get information about the number of years car owners keep their cars. A random sample of 25 car owners resulted in ?̅ = 7.01 years, and ? = 3.74 years. Assume that the sample is drawn from a normally distributed population.
A random sample of 100 observations from a population yields a mean equal to 10 and a standard deviation equal to 6. A 90% confidence interval for the mean of the population is(a) 10 ± 0.9870
(b) 10 ± 1.0248
(c) 10 ± 1.0266
(d) 10 ± 1.1760
(e) None of these
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