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Question
Math
Posted 8 months ago

An airline transports over 10,000 passengers daily, and the airline is curious what proportion of their passengers use mobile boarding passes instead of paper passes. They take an SRS of 80 passengers and find that 60 of them use mobile boarding passes.

Based on this sample, which of the following is a 95%95 \% confidence interval for the proportion of passengers who use mobile boarding passes?

Choose 1 answer:
(A) (0.625,0.875)(0.625,0.875)
(B) (0.637,0.863)(0.637,0.863)
(c) (0.655,0.845)(0.655,0.845)
(D) (0.670,0.830)(0.670,0.830)
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Answer from Sia
Posted 8 months ago
Solution by Steps
step 2
Find the standard error (SE) of the sample proportion using the formula SE=p^(1p^)nSE = \sqrt{\frac{p̂(1 - p̂)}{n}}, where nn is the sample size: SE=0.75(10.75)80SE = \sqrt{\frac{0.75(1 - 0.75)}{80}}
step 3
Calculate the value of the standard error: SE=0.750.2580=0.187580=0.002343750.0484SE = \sqrt{\frac{0.75 \cdot 0.25}{80}} = \sqrt{\frac{0.1875}{80}} = \sqrt{0.00234375} \approx 0.0484
step 4
Determine the z-score for a 95% confidence interval, which is approximately 1.96 for a two-tailed test
step 5
Calculate the margin of error (ME) using the z-score and the standard error: ME=zSE=1.960.04840.0949ME = z \cdot SE = 1.96 \cdot 0.0484 \approx 0.0949
step 6
Find the lower and upper bounds of the 95% confidence interval by subtracting and adding the margin of error to the sample proportion: lower bound =p^ME=0.750.09490.6551= p̂ - ME = 0.75 - 0.0949 \approx 0.6551 and upper bound =p^+ME=0.75+0.09490.8449= p̂ + ME = 0.75 + 0.0949 \approx 0.8449
step 7
Round the lower and upper bounds to three decimal places: lower bound 0.655\approx 0.655 and upper bound 0.845\approx 0.845
C
Key Concept
Confidence Interval for a Proportion
Explanation
The confidence interval for a proportion is calculated using the sample proportion, the z-score corresponding to the desired confidence level, and the standard error of the sample proportion. It provides a range of values within which the true population proportion is likely to fall.

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