1. Sampling Techniques Module 5Santa Rosa Science And Technology HighSchoolBasic Statistics Ms. Ma. Cristina C. Pegollo

2. Sample ProblemSuppose Ms. Bambasi wants to determine the weekly food expenditure of students, if there are 1000 students and the guidance counselor decided to use only 100 students as a sample, who will be included in the sample? 3. DEFINITIONSampling technique is aprocedure used to determinethe individuals or members of asample. 4. Sampling TechniquesProbabilityNon-ProbabilitySampling Sampling Convenience Random SamplingSamplingSystematic Quota Sampling Sampling Stratified Random Purposive SamplingSamplingCluster SamplingMulti-Stage Sampling 5. PROBABILITY Samplingeach eligible member of the population has a specific and known chance ofbeing included in the sample.When using this technique, it is important to have a complete list of the members of the population 6. NON-PROBABILITY SamplingMembers of the sample size are drawn based on the judgment of the researcher.Sometimes, referred to as subjectivesampling. 7. Probability Sampling1. Simple Random Sampling Lottery Method - write the names or codes on a piece ofpaper, put them in a container, thenrandomly select the desired number of samples. Sometimes referred to as thefishbowl technique. 8. Probability Sampling1. Simple Random Sampling Random Numbers a table of random numbers, computer or calculator can be used to generate random numbers. This is perhaps a more convenient way of selecting your random sample. The randomly produced digits can be used to pick your samples. However, a complete listing of the members of the population is needed. 9. Probability Sampling2. Systematic Sampling choose a starting point then select every kth element of the population using 10. ExampleChoose a sample of size 5 from N = 45, using systematic random sampling.Solution:Step 1: Determine k;, this means thatyou have to include every 9th member of thepopulation after choosing a random start.Step 2: You can employ the lottery method to get arandom start. Suppose you picked 4.Step 3: Getting 5 members you will have: 4, 13,22, 31, and 40 11. Probability Sampling3. Stratified Random Sampling thepopulation is subdivided into atleast two different subpopulations(or strata) that share the samecharacteristics (such as gender),then draw a sample from eachstratum. 12. ExampleBrgy. Market Area consists of 10,000 families belonging to different income brackets. A survey to find out how many are in favor of the RH bill will be conducted. To ensure that all income groups are represented, respondents will be divided into High-Income, Average-Income, and Low-Income. Below is the distribution of income groups. StrataNumber of FamiliesHigh Income 2 000 Average Income 5 000Low-Income3 000N = 10 000 13. Cont 1. Using a 5% margin of error, how many familiesshould be included in the sample? UsingSlovins Formula, you should get 385. 2. Using either proportional or equal allocation ,how many from each group should be taken assamples? See the table belowStrataNumber Percent ProportionalEqualofFamiliesHigh-Income2 000 0.2(385) = 77 385/3 = 128 Average-5 0000.5(385) =129Income 193Low- Income3 0000.3(385) =128 11510 000100% 385385 14. Probability Sampling4.Cluster Sampling divide thepopulation area into sections (orclusters), then randomly select a fewof those sections, and then yourandomly select a sample from thoseselected sections. 15. ExampleSuppose we want to determine the average daily expenses of families living in the City of Santa Rosa. Assume that there are 15 barangays. We can draw a random sample of 5 barangays using random sampling and then get a certain number of families from each of the 5 barangays. 16. Probability Sampling5. Multi-Stage Sampling combination ofseveral sampling techniquesdiscussed. 17. Non-Probability Sampling1. Convenience Sampling simply use resultsthat are readily available. Hey! Do you believe in love at first sight? 18. Non-Probability Sampling2. Quota Sampling - the researcher firstidentifies the stratums and their proportions asthey are represented in the population. Thenconvenience or judgment sampling is used toselect the required number of subjects fromeach stratum.Selectedthroughresearchers convenience or judgment. 19. Non-Probability Sampling3. Purposive Sampling selects members orelements based on the particular purpose of theexperiment or study. This technique is useful forsituations where you need to reach a targetedsample quickly and where sampling forproportionality is not the primary concern. 20. Sample Problem Suppose Ms. Bambasi wants todetermine the weekly food expenditureof students, if there are 1000 studentsand the guidance counselor decided touse only 100 students as a sample, whowill be included in the sample?Activity. With your partner, help Ms.Bambasi decide on which samplingtechnique she should use in selectingstudents for her sample. Present herthree choices. (Bond Paper) 21. Exercises:Identify which sampling technique was used in thefollowing scenarios.1. When she wrote Women and Emoticons, authorKC Pascual based conclusions on 4500responses from 100,000 questionnairesdistributed to women.2. The Guidance Counselor at Santa Rosa HighSchool surveys all students from each of 20randomly selected classes.3. A sociologist at the College of StaRSci selects15 men and 15 women from each of 4 MathClasses. 22. Cont4. IBM selects every 200th compact disk from the assembly line ad conducts a thorough test of quality.5. The court secretary writes the name of each Municipal Judge on a separate card, shuffles the cards , and then draws 3 names.6. The marketing manager of Ebay.ph tests a new sales strategy by randomly selecting 150 consumers with less than P100 000 in gross income and 150 consumers with gross income of at least P100 000.7. Pro-RH bill lobbyists polls 300 men and 300 women about their views concerning the use of contraceptives. 23. Cont.8.A market researcher for Champion Detergentinterviews all passengers on each of 10randomly selected PUVs.9. A medical researcher from Multiliver Phils.interviews all leukemia patients in each of 20randomly selected hospitals.10. In conducting research for the evening news, areported for ABC-CBN interviews 15 people asthey leave SM Santa Rosa. 24. B. Solve the following1. A researcher would like to investigate the perception of students of Mathematics. He divided the population into sub-populations as shown below. Use stratified random sampling if the sample to be drawn consists of 500 students. Strata Number ofStudents First Year 1600 Second Year1500 Third Year 1400 Fourth Year1000 25. 2. A journalist would like to know the most favorite noontime show for this month. He decided to conduct a survey on 5 barangays. The table below shows the list of barangay and the number of residents in each barangay. Use stratified random sampling to draw 1 000 residents who will be included in the survey.Barangay Number of ResidentsMapayapa 2 000Malinis1 000Mahangin 1 500Mabunga2 500Masaya 1 500