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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.

A random sample of international flights in 20132013 showed that 79% 79 \% of the flights arrived within 1515 minutes of their scheduled arrival time, and this estimate had a margin of error of 3% 3 \% at a 95% 95 \% confidence level. Which of the following conclusions is best?\newlineChoose 11 answer:\newline(A) Exactly 79% 79 \% arrived within 1515 minutes of their scheduled times.\newline(B) Exactly 76% 76 \% arrived within 1515 minutes of their scheduled times.\newline(C) Between 76% 76 \% and 82% 82 \% arrived within 1515 minutes of their scheduled times.\newline(D) Between 92% 92 \% and 98% 98 \% arrived within 1515 minutes of their scheduled times.

Full solution

Q. A random sample of international flights in 20132013 showed that 79% 79 \% of the flights arrived within 1515 minutes of their scheduled arrival time, and this estimate had a margin of error of 3% 3 \% at a 95% 95 \% confidence level. Which of the following conclusions is best?\newlineChoose 11 answer:\newline(A) Exactly 79% 79 \% arrived within 1515 minutes of their scheduled times.\newline(B) Exactly 76% 76 \% arrived within 1515 minutes of their scheduled times.\newline(C) Between 76% 76 \% and 82% 82 \% arrived within 1515 minutes of their scheduled times.\newline(D) Between 92% 92 \% and 98% 98 \% arrived within 1515 minutes of their scheduled times.
  1. Problem statement: The problem states that 79%79\% of the flights arrived within 1515 minutes of their scheduled arrival time with a margin of error of 3%3\% at a 95%95\% confidence level. To find the range, we need to add and subtract the margin of error from the estimated percentage.
  2. Calculate lower bound: Calculate the lower bound of the confidence interval by subtracting the margin of error from the estimated percentage.\newlineLower bound = Estimated percentage - Margin of error\newlineLower bound = 79%3%79\% - 3\%\newlineLower bound = 76%76\%
  3. Calculate upper bound: Calculate the upper bound of the confidence interval by adding the margin of error to the estimated percentage.\newlineUpper bound = Estimated percentage + Margin of error\newlineUpper bound = 79%+3%79\% + 3\%\newlineUpper bound = 82%82\%
  4. Determine range: Now we have the range for the confidence interval.\newlineThe range is from 76%76\% to 82%82\%.
  5. Compare with options: Compare the range with the given options to determine the best conclusion.\newlineOption (C) states "Between 76%76\% and 82%82\% arrived within 1515 minutes of their scheduled times," which matches our calculated range.

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