Python (All numbers and graphs need to be produced using Python)

The file trees.csv provides measurements of the diameter (in inches) and volume of timber (in cubic feet) from 31 black cherry trees. The first column of the data contains the ID for each tree, which is a number from 1 to 31.

a) [2 points] Make a scatterplot placing diameter on the x-axis and volume on the y-axis. Explain in words: what kind of pattern (i.e. direction, form and strength) does your plot show?

b) [2 points] Find the Pearson correlation coefficient r between diameter and volume. Explain in words: what does it tell us?

c) [3 points] The tree corresponding to ID = 21 has a diameter of 14 and a volume of 34.5. Replace the volume of this tree by 100 and recalculate the correlation r from part b).

d) [2 points] Explain in words: Did the correlation computed in part c) between distance and time change in comparison to the one found in part b)? Why or why not? (It is optional to draw another scatterplot for the modified data.)