The mean arrival rate of flights at O'Hare Airport in marginal weather is 195 flights per hour with a historical standard deviation of 16 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. 287 284 175 193 208 187 213 228 176 213 284 206 224 216 186 184 216 284 209 186 215 204 216 224 184 197 176 181 197 175 (b-1) Calculate the test statistic. (Round your answer to 2 decimal places.) Test statistic