11.32 Three samples of each of three types of PVC pipe of equal wall thickness are tested to failure under three temperature ...

        11.32 Three samples of each of three types of PVC pipe   of equal wall thickness are tested to failure under three temperature   conditions, yielding the results shown below. Research questions: Is mean   burst strength affected by temperature and/or by pipe type? Is there a “best”   brand of PVC pipe? Explain.          Burst   Strength of PVC Pipes (psi)     Temperature   PVC1 PVC2 PVC3     Hot   (70° C) 250 301 235      273 285 260       281 275 279       Warm   (40° C) 321 342 302     322 322 315       299 339 301       Cool   (10° C) 358 375 328      363 355 336       341 354 342