Specimens of three di erent types of rope wire were selected, and the fatigue limit (MPa) was determined for each specimen, resulting in the accompanying data.
Type 1 350 350 350 358 370 370 370 371 371 372
372 384 391 391 392
Type 2 354 359 363 365 368 369 371 350 374 376
380 383 388 392 373
Type 3 361 362 364 364 365 366 371 377 377 379
380 380 392 350 377
(a) Compare the variations in three types using their respective sample standard deviations.
(b) Compare the variations in three types using their respective coecient of variations (CV).
(c) Now compare the conclusions of part (a) and part (b). Are they in consensus with each other?
(d) In general, which measure would you prefer to use to compare variations? Why?