Question 255312
The mean arrival rate of flights at O Hare Airport in marginal weather is 195 Flights per hour. To increase arrivals, a new air traffic control procedure is implemented. In the next 30 days of marginal weather the mean arrival rate is 200 flights per hour with a standard deviation of 13 flights. 
A) What is the appropriate null and alternate hypothesis to determine if there has been a significant increase in the mean number of arrivals per hour? 
Ho: u = 195
Ha: u > 195
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B) Using alpha 0.025, what is the critical value for the hypotheses test?
Right-tail test with alpha = 2.5%: z = 1.96
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C) What is the test statistic for the hypothesis test?
z(200) = (200-195)/13 = 0.3846
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Conclusion: Since the ts is not in the reject interval, do not reject Ho.
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Cheers,
Stan H.