An airline, in response to passenger concern, conducts realistic tests to determ

Question

An airline, in response to passenger concern, conducts realistic tests to determine the time needed to evacuate a Boeing 737. Average evacuation time in the past has been 100 seconds with a standard deviation of 15 seconds. Assume the amount of time to evacuate a planeload of passengers is approximately normally distributed. What is the probability that an individual planeload of passengers can be evacuated in less than 92 seconds? a. 0.0800 b. 0.2981 c. 0.3849 d. 0.7019 If the airline conducts a sample of 30 tests, what is the probability that the average evacuation time will be 96 seconds or less? a.0.1406 b. 0.1064 c. 0. 0721 d. 0.0228

Explanation / Answer

4) P(X<92)=P(Z<(92-100)/15)=P(Z<-0.5333)=0.2981

therefore option B is correct

5) here std error of mean =std deviation/(n)1/2 =15/(30)1/2 =2.7386

therefore P(X<96)=P(Z<(96-100)/2.7386)=P(Z<-1.4606)=0.0721

therefore option C is correct

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