EXAMPLE 13 Systematic sampling

20richest

Table 9 contains the top 20 richest people in the world for the year 2014, according to the annually published Forbes 400 listing. Obtain a systematic sample from this list, using .

Table 1.21: TABLE 9 Twenty richest people in the world
Rank Name Net worth
($ billions)		 Rank Name Net worth
($ billions)
1 Bill Gates 72 11 Sheldon Adelson 28.5
2 Warren Buffett 58.5 12 Jeff Bezos 27.2
3 Larry Ellison 41 13 Larry Page 24.9
4 Charles Koch 36 14 Sergey Brin 24.4
5 David Koch 36 15 Forrest Mars 20.5
6 Christy Walton 35.4 16 Jacqueline Mars 20.5
7 Jim Walton 33.8 17 John Mars 20.5
8 Alice Walton 33.5 18 Carl Icahn 20.3
9 S. Robson Walton 33.3 19 George Soros 20
10 Michael Bloomberg 31 20 Mark Zuckerberg 19
Table 1.21: Source: Forbes magazine, www.forbes.com/forbes-400/list/.

23

Solution

First, we randomly select a whole number between 1 and . Suppose we select 2. Thus, our systematic sample will consist of every 4th person in Table 9, starting with the 2nd person. That is, our systematic sample will consist of the 2nd, 6th, 10th, 14th, and 18th persons, shown here:

Systematic sample: Warren Buffett, Christy Walton, Michael Bloomberg, Sergey Brin, Carl Icahn.

NOW YOU CAN DO

Exercises 11–14.