A random sample of international flights in 2013 showed that 79% of the flights arrived within 15 minutes of their scheduled arrival time, and this estimate had a margin of error of 3% at a 95% confidence level. Which of the following conclusions is best?Choose 1 answer:(A) Exactly 79% arrived within 15 minutes of their scheduled times.(B) Exactly 76% arrived within 15 minutes of their scheduled times.(C) Between 76% and 82% arrived within 15 minutes of their scheduled times.(D) Between 92% and 98% arrived within 15 minutes of their scheduled times.
Q. A random sample of international flights in 2013 showed that 79% of the flights arrived within 15 minutes of their scheduled arrival time, and this estimate had a margin of error of 3% at a 95% confidence level. Which of the following conclusions is best?Choose 1 answer:(A) Exactly 79% arrived within 15 minutes of their scheduled times.(B) Exactly 76% arrived within 15 minutes of their scheduled times.(C) Between 76% and 82% arrived within 15 minutes of their scheduled times.(D) Between 92% and 98% arrived within 15 minutes of their scheduled times.
Problem statement: The problem states that 79% of the flights arrived within 15 minutes of their scheduled arrival time with a margin of error of 3% at a 95% confidence level. To find the range, we need to add and subtract the margin of error from the estimated percentage.
Calculate lower bound: Calculate the lower bound of the confidence interval by subtracting the margin of error from the estimated percentage.Lower bound = Estimated percentage - Margin of errorLower bound = 79%−3%Lower bound = 76%
Calculate upper bound: Calculate the upper bound of the confidence interval by adding the margin of error to the estimated percentage.Upper bound = Estimated percentage + Margin of errorUpper bound = 79%+3%Upper bound = 82%
Determine range: Now we have the range for the confidence interval.The range is from 76% to 82%.
Compare with options: Compare the range with the given options to determine the best conclusion.Option (C) states "Between 76% and 82% arrived within 15 minutes of their scheduled times," which matches our calculated range.
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