What proportion of commercial airline pilots are more than 40 years of age? Suppose an analyst has access to a list of all pilots who are members of the Air Line Pilots Association. If this list is used as a frame for the study, she can randomly select a sample of pilots, contact them, and ascertain their ages. From 89 of these pilots so selected, she learns that 48 are more than 40 years of age. Construct an 85% confidence interval to estimate the population proportion of commercial airline pilots who are more than 40 years of age.
A) What proportion of commercial airline pilots are more than 40 years of age? Suppose an analyst has access to a list of all pilots who are members of the Air Line Pilots Association. If this list is used as a frame for the study, she can randomly select a sample of pilots, contact them, and ascertain their ages. From 89 of these pilots so selected, she learns that 48 are more than 40 years of age. Construct an 85% confidence interval to estimate the population proportion of commercial airline pilots who are more than 40 years of age.
B) Suppose you want to estimate the proportion of cars that are sport utility vehicles (SUVs) being driven in Regina at rush hour by standing on the corner of Victoria Avenue and Albert Street and counting SUVs. You believe the figure is no higher than 0.40. If you want the error of the confidence interval to be no greater than 0.03, how many cars should you randomly sample? Use a 90% level of confidence.
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