22. The article Nonbloated Burned Clay Aggregate Concrete (J. Materials, 1972: 555—563) reports the following data on 7-day exural strength of nonbloated burned clay aggregate concrete samples

(psi):

257 327 317 300 340 340 343 374 377 386 383 393 407 407 434 427 440 407 450 440 456 460 456 476 480 490 497 526 546 700 Test at level .10 to decide whether exural strength is a normally distributed variable.