Install package MASS. Then use the follow code to explore data set trees.

a$).$ How many rows and what are the variables names?

b$).$ Display the first $6$ rows of data set.

c$).$ Display the first $3$ rows and the first $2$ columns of the data.

d$).$ Display the $10$ th to $15$ th rows.

e$).$ Display the $10$th row and the $3$ column.

f$).$ Calculate the mean and standard deviation of the variable Volume.

g$).$ Generate a boxplot of vairalbe Girth.

h$).$ Plot a scatter plot of Volume against Height. $.$