Lianas are woody vines that grow in tropical forests. Researchers measured liana abundance (stems/ha) in several plots in the central Amazon region of Brazil. The plots were classified into two types: plots that were near the edge of the forest (less than 100 meters from the edge) or plots far from the edge of the forest. The raw data are given and are summarized in the table.

(a) Make normal probability plots of the data to confirm that the distributions are mildly skewed.
(b) Conduct a t test to compare the two types of plots at α = 0.05. Use a nondirectional alternative.
(c) Apply a logarithm transformation to the data and repeat parts (a) and (b).
(d) Compare the t tests from parts (b) and (c). What do these results indicate about the effect on a t test of mild skewness when the sample sizes are fairly large?

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Mean SD Near 34 438 125 34 368 114 FI Far Near Far 639 601 600470 339 384 605 581 555 309 395 393 535 531 466236 252 407 437 423 380 241 215 427 376 362 350320 228 445 349 346 337325 267 451 320 317 310352 294 493 285 271 265 275 356 502 250 450 44 181 418 540 436 432 420 250 425 590 419 407 702 676 266 495 338 648