The accompanying data set contains three variables, x₁, x₂, and x₃.
a. Bin the values of x₁ into three equal-size groups. Label the groups with numbers 1 (lowest values) to 3 (highest values). How many observations are assigned to group 1?
b. Bin the values of x₂ into three equal-interval groups. Label the groups with numbers 1 (lowest values) to 3 (highest values). How many observations are assigned to group 2?
c. Bin the values of x₃ into the following three groups: < 50,000, between 50,000 and 100,000, and > 100,000. Label the groups with numbers 1 (lowest values) to 3 (highest values). How many observations are assigned to group 1?