Import data from the Black Spruce Case Study in Section 1.9 into R.
(a) Compute the numeric summaries for the height changes (Ht.Change) of the seedlings.
(b) Create a histogram and normal quantile plot for the height changes of the seedlings. Is the distribution approximately normal?
(c) Create a boxplot to compare the distribution of the change in diameters of the seedlings (Di.change) grouped by whether or not they were in fertilized plots.
(d) Use the tapply command to find the numeric summaries of the diameter changes for the two levels of fertilization.
(e) Create a scatter plot of the height changes against the diameter changes and describe the relationship