Math 120 Control Charts Section 6.1 The manager of Motel 11 has 316 rooms in Palo Alto, California. From observation over a long period of time, she knows that on an average night, 268 rooms will be rented. The long‐term standard deviation is 12 rooms. The distribution is approximately mound‐shaped and symmetrical. a. For 10 consecutive nights, the following numbers of rooms were rented each night. Night 1 2 3 4 5 6 7 8 9 10 Number 234 258 265 271 283 267 290 286 263 240
of Rooms Make a control chart for the number of rooms rented each night and plot the preceding data on the control chart. Question: Would you say the number of rooms rented during this 10‐night period has been unusually low? Unusually high? About what is expected? Explain your answer. b. For another 10 consecutive nights, the following numbers of rooms were rented each night. Night 1 2 3 4 5 6 7 8 9 10 Number 238 245 261 269 273 250 241 230 215 217
of Rooms Make a control chart for the number of rooms rented each night and plot the preceding data on the control chart. Question: Would you say the number of rooms rented during this 10‐night period has been unusually low? Unusually high? About what is expected? Explain your answer. Identify all out‐of‐control signals by Type I, II, or III.