The accompanying data set contains two numerical variables, x₁ and x₂.
a. For x₂, how many of the observations are equal to 2?

b. Sort x₁ and then x₂, both in ascending order. After the variables have been sorted, what is the first observation for x₁ and x₂?

c. Sort x₁ and then x₂, both in descending order. After the variables have been sorted, what is the first observation for x₁ and x₂?

d. Sort x₁ in ascending order and x₂ in descending order. After the variables have been sorted, what is the first observation for x₁ and x₂?

e. How many missing values are there in x₁ and x₂?