2. Consider the accompanying data on plant growth after the application of different types of growth hormones. H1 H2 H3 H4 H5 13 21 18 7 6 17 13 15 11 11 7 20 20 18 15 14 17 17 10 8 (a) Is there evidence of a difference in mean growth among the five different hormone treatment? Use a = 0.05. What assumptions have you used? (b) Find a 90% confidence interval for the mean difference in plant growth for plants treated with hormone 2 and hormone 5. (c) Find a 90% confidence interval for the mean growth for plants receiving hormone 2