SOLUTION: Travel weekly international air transport association survey asked business travelers about the purpose for their most recent business trip. 19% responded that it was for an intern

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Question 825323: Travel weekly international air transport association survey asked business travelers about the purpose for their most recent business trip. 19% responded that it was for an internal company visit. Supposed 950 travelers were randomly selected.
A. What is the probability that more than 25% of the business travelers say that the reason for their most recent business trip was an internal company visit?
B. What is the probability that between 15% and 20% of the business travelers say that the reason for their most recent business trip was an internal company visit?
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
Travel weekly international air transport association survey asked business travelers about the purpose for their most recent business trip. 19% responded that it was for an internal company visit. Supposed 950 travelers were randomly selected.
A. What is the probability that more than 25% of the business travelers say that the reason for their most recent business trip was an internal company visit?
z(0.25) = (0.25-0.19)/sqrt[0.19*0.81/950] = 4.7140
P(p-hat>0.25) = P(z > 4.7140) = 0.00000122
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B. What is the probability that between 15% and 20% of the business travelers say that the reason for their most recent business trip was an internal company visit?
z(0.15) = (0.15-0.19)/sqrt[0.19*0.81/950] = -3.9284
z(0.20) = (0.20-0.19)/sqrt[0.19*0.81/950] = 0.7857
P(0.15< p-hat <0.20)
= P(-3.9284< z <0.7857)
= normalcdf(-3.9284,0.7857)
= 0.7839
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Cheers,
Stan H.
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