The percentage result of members per subgroup will be multiplied from the computed totalsample size. After obtaining the sample size per strata, then simple random sampling will bedone for the selection of samples from each group.Sample Size per Subgroups180/600=.30x 240=72 Grade 7 students160/600=.27x 240=65 Grade 8 students150/600=.25x 240=60 Grade 9 students110/600=.18x 240=43 Grade 10 students100%240 respondentsCluster Sampling.This procedure is usually applied in large-scale studies,geographical spread out of the population is a challenge, and gathering information will bevery time-consuming. Similar to stratified random sampling, cluster sampling also involvesgrouping of the population according to subgroups or clusters. It is a method where multipleclusters of people from the chosen population will be created by the researcher in order tohave homogenous characteristics.For example, a researcher would like tointerview of all public senior high school studentsacross Mindanao. As a researcher cluster will beselected to satisfy the plan size. In the given example,the first cluster can be by region, the second clustercan be by division, and the third cluster can be bydistrict.Another way of doing cluster sampling isillustrated on the figure on the right side.Systematic Sampling.This procedure is as simple as selecting samples everynth(example every 2nd, 5th) of the chosen population until arriving at a desired total number ofsample size. Therefore the selection is based on a predetermined interval. Dividing thepopulation size by the sample size, the interval will be obtained. For example, from a totalpopulation of 75, you have 25 samples; using systematic sampling, you will decide to selectevery 3rdperson on the list of individuals.
