Five different varieties of oats were planted in each of four separated fields. The following yields resulted. Field Oat variety 1 2 3 4 1 296 357 340 348 2 402 390 420 335 3 345 342 358 308 4 360 322...

Five different varieties of oats were planted in each of four separated fields. The following yields resulted.

Find out whether the data are consistent with the hypothesis that the mean yield does not depend on

(a) The field

(b) The oat variety

Use the 5 percent level of significance.