SAMPLING Flashcards
CENSUS VS SAMPLE
Census - Complete enumeration of the population
Sample - a subgroup of the elements of the population selected for study
Defining Target Population
Define in terms of Element (the respondent - from whom information is desired) Sampling Unit - Where the respondent is Extent - Geographic Time
Defining the Sampling Frame
A list of all sampling elements or units OR a set of directions for obtaining target population
Sampling Frame Error
A list may omit some elements of the desire population or include those who do not belong
Preventing Error
Redefining population in terms of sampling frame
screening respondents
Adjusting data by weighting
Classification of Techniques
Nonprobability –> Convenience, Judgemental, Quota, Snowball
Probability –> Simple Random, Systematic, Stratified, Cluster
CONVENIENCE sampling
a sample of covenient elements - people they could get
JUDGEMENTAL sampling
population elements are selected based on judgement of researcher
QUOTA sampling
two stage restricted judgemental sampling - develop contrl categories, sample ements based on convenience/judgement
SNOWBALL sampling
An inital group sampled then identify others who belong to interest group.
SIMPLE RANDOM sampling
Each element of population has known and equal probability of selection.
SYSTEMATIC sampling
Sample is chosen from a random starting point and is then picked every ith element in succession.
STRATIFIED samplin
two step process. population is partitioned into strata/sub poplations (that covers whole population element) then random procedure (SRS) selects from groups
CLUSTER sampling
target population is dvidied into mutually exclusive and collectively exhaustion subpopulations -> then random sample of clusters is selected via SRS
