The mean arrival rate of flights at O'Hare Airport in marginal weather is 195 flights per hour with a historical standard deviation of 13 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 200 flights per hour, (a) Set up a right-tailed decision rule at alpha = .025 to decide whether there has been a significant increase in the mean number of arrivals per hour, (b) Carry out the test and make the decision. Is it close? Would the decision be different if you used alpha = .01? (c) What assumptions are you making, if any? Flights 210 215 200 189 200 213 202 181 197 199 193 209 215 192 179 196 225 199 196 210 199 188 174 176 202 195 195 208 222 221

He cheyenne hotel in big sky, montana, has accumulated records of the total electrical costs of the hotel and the number of occupancy-days over the last year. an occupancy-day represents a room rented out for one day. the hotel's business is highly seasonal, with peaks occurring during the ski season and in the summer. month occupancy- days electrical costs january 1,736 $ 4,127 february 1,904 $ 4,207 march 2,356 $ 5,083 april 960 $ 2,857 may 360 $ 1,871 june 744 $ 2,696 july 2,108 $ 4,670 august 2,406 $ 5,148 september 840 $ 2,691 october 124 $ 1,588 november 720 $ 2,454 december 1,364 $ 3,529 required: 1. using the high-low method, estimate the fixed cost of electricity per month and the variable cost of electricity per occupancy-day. (do not round your intermediate calculations. round your variable cost answer to 2 decimal places and fixed cost element answer to nearest whole dollar amount) 2. what other factors other than occupancy-days are likely to affect the variation in electrical costs from month to month? (you may select more than one answer. single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer.) seasonal factors like winter or summer. systematic factors like guests, switching off fans and lights. number of days present in a month. fixed salary paid to hotel receptionist. income taxes paid on hotel income.