In: Statistics and Probability
The mean arrival rate of flights at O'Hare Airport in marginal weather is 195 flights per hour with a historical standard deviation of 17 flights. To increase arrivals, a new air traffic control procedure is implemented. In the next 30 days of marginal weather, the mean arrival rate is 201 flights per hour. |
223 | 190 | 214 | 196 | 178 | 184 | 183 | 217 | 215 | 175 |
217 | 222 | 181 | 215 | 213 | 207 | 216 | 193 | 224 | 215 |
220 | 176 | 183 | 188 | 186 | 209 | 219 | 185 | 178 | 208 |
Click here for the Excel Data File |
(a) |
Set up a right-tailed decision rule at α = .025 to decide whether there has been a significant increase in the mean number of arrivals per hour. Choose the appropriate hypothesis. |
a. | H1: μ > 195, reject H1 if z < 1.960 |
b. | H1: μ < 195, reject H1 if z > 1.960 |
c. | H0: μ ≥ 195, reject H0 if z < 1.960 |
d. | H0: μ ≤ 195, reject H0 if z > 1.960 |
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(b-1) |
Calculate the test statistic. (Round your answer to 2 decimal places.) |
Test statistic |
(b-2) | What is the conclusion? |
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(b-3) | Would the decision have been different if you used α = .01? |
a. |
No, z.01 = 2.33 and 1.93 < 2.33, so we would still have concluded that there is no evidence to indicate a significant increase. |
b. |
Yes, z.01 = 2.33 and 1.93 < 2.33, so we would still have concluded that there has been a significant increase in the average number of flight departures. |
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(c) | What assumptions are you making, if any? |
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a)
d.H0: μ ≤ 195, reject H0 if z > 1.960
b-1)
test statistic z =1.93
b-2)
There has not been a significant increase in the average number of flight departures
No, z.01 = 2.33 and 1.93 < 2.33, so we would still have concluded that there is no evidence to indicate a significant increase.
We have assumed a normal population or at least one that is not badly