Population and sampling design example

Try to write your population and sampling design in details. (choose one topic)

 

1.You would like to do a self-filled survey among the students in senior high schools about relationship of obesity and internet addiction. 

2.You plan to do face-to-face interviews among the residents in nursing homes to investigate the issue about quality of care.

 

Answer:

I choose topic #1. I would like to do a self-filled survey among the students in senior high schools about relationship of obesity and internet addiction, so it clear that the theoretical population is senior high school students. For this exercise I want to do the survey to represent the urban students of my home city: Yogyakarta (in Indonesia) which I can get access to, so the study population is senior high school students in Yogyakarta.

It is costly and unpractical to do physical face-to-face paper-based survey at this time. I planned to ask the participants to fill an online survey form. The sampling frame of this study is the students’ email list, which virtually all urban students now have their email address registered in the city’s Office of Education. I shall ask the Office of Education of Yogyakarta to access the database of high school students.

There are 81 high schools in Yogyakarta with about a total of 25,000 students. Prevalence of obesity in urban setting of Indonesia based on Basic Health Research (RISKESDAS) 2018 is 5.9%.

The sample size for the study was determined using single population proportion formula. Specifications made during the computation with formula available at https://select-statistics.co.uk/calculators/sample-size-calculator-population-proportion/ were: 5.9% expected prevalence of obesity, 99% confidence level, 3% margin of error, and population size of 25,000. The result of calculation was 403, then I add 20% compensation for possible non-response, the final sample size was 484.

Samples were selected using systematic sampling technique. Sample was drawn from the database, every 51^st email in the sequence (25000/484=51,65).

 

In summary:

1.     Theoretical population: senior high school students

2.     Study population: senior high school students in Yogyakarta à 25,000

3.     Sampling frame: email database of the students

4.     Sample size: 484

5.     Sampling technique: systematic sampling