For a given data set, there are nine deciles, denoted by D₁, D₂, ???, D⁹, which separate the sorted data into 10 groups, with about 10% of the values in each group. There are also four quintiles, which divide the sorted data into 5 groups, with about 20% of the values in each group. (Note the difference between quintiles and quantiles, which were described earlier in this section.)

a. Using the movie budget amounts in Table 3-4 on page 116, find the deciles D₁, D₇, and D₈.

b. Using the movie budget amounts in Table 3-4, find the four quintiles.

Table 3-4 Sorted Movie Budget Amounts (in millions of dollars) 4.5 5 6.5 7 20 20 29 30 35 40 40 41 50 52 60 65 68 68 70 70 70 72 74 75 80 100 113 116 120 125 132 150 160 200 225