In: Statistics and Probability
Determine the individuals who will be administered the survey. Randomly select a number from 1 to k. Suppose that we randomly select 6. Starting with the first individual selected, the individuals in the survey will be nothing, nothing, nothing..., nothing.
This is a systematic sampling problem.
systematic sampling: It is a type of probability sampling method in which sample members from a larger population are selected according to a random starting point and a fixed, periodic interval. This interval, called the sampling interval (k), is calculated by dividing the population size(N) by the desired sample size(n).
Here, we are given a problem where we have to select indiviaduals for a survey from N number of individuals having a systematic sample size, n, such that k = N/n
In order to determine the individuals who will be administered the survey, we randomly select a number from 1 to k, in this case the number is 6.
this means, the first individual selected in the survey will be 6 and others will be followed by a gap of k until we reach a number that is less than or equal to the total number of subjects N
i.e., the individuals who will be administered the survey, are:
6, 6+k, 6+2k, 6+3k,........6+mk
such that, 6+mk N where m is positive integer.
To understand this better, consider the following problem as an example:
The human resource department at a certain company wants to conduct a survey regarding worker benefits. The department has an alphabetical list of all 5780 employees at the company and wants to conduct a systematic sample of size 60.
What is k?
answer: here, N=5780; n=60
we will compute k as:
k = N/n = 5780/60 = 96.33 96 (as sample size must be a wwhole number)
now, the next part of the question:
Determine the individuals who will be administered the survey. Randomly select a number from 1 to k. Suppose that we randomly select 6. Starting with the first individual selected, the individuals in the survey will be nothing, nothing, nothing..., nothing.
starting with 6, the individuals in the survey will be:
6, 6+k, 6+2k, 6+3k,........6+mk
i.e., 6, 6+96, 6+2*96,.........., 6+60*96 [as 6+60*96 = 5766 < 5780]
the individuals in the survey for this example will be:
6,102,198,.......,5766
Hope this helped!