34 petri dishes are prepared with a growth medium. 16 are randomly selected and treated with antibiotic a. the other 18 are treated with antibiotic b. each dish is inoculated with a bacteria. several hours later, the diameter of the bacteria colony in each dish is measured in mm, with these results: a: 8.59, 7.80, 4.11, 8.68, 8.08, 7.86, 6.97, 8.21, 1.72, 8.13, 7.48, 6.33, 8.32, 8.65, 3.06, 8.90 b: 5.59, 6.96, 5.25, 6.46, 0.09, 7.70, 3.10, 0.94, 7.00, 7.91, 6.39, 7.45, 5.79, 6.66, 5.91, 6.62, 5.07, 7.25 let µa and µb be the respective population mean diameters across many similar hypothetical experiments. consider a test at level α = 0.10 of h0 : µa − µb = 0 vs. ha : µa − µb 6= 0. (a) do you think it is plausible that the samples came from approximately normal distributions? why or why not? (b) use r to run a wilcoxon rank sum test to evaluate h0.