[06.04a] Sampling Design Part 1 V2.pdf

A smaller (but hopefully representative) collection of units from a population used to determine truths about that population

What is the definition of a sample (Field, 2005)?

Resources (time, money) and workload

What are the primary reasons researchers engage in sampling?

Every five years

How often are censuses typically conducted because yearly data collection is impractical?

Gives results with known accuracy that can be calculated mathematically

What benefit does sampling provide regarding the accuracy of results?

Sample size

What is known accuracy related to, regarding confidence interval calculations?

The list from which the potential respondents are drawn

What is the definition of the sampling frame?

Community map or Patient listings

What are two examples of documents that can serve as a sampling frame?

Completeness and being up-to-date

What two qualities of a sampling frame must be assessed before using it?

Probability sampling

What type of sampling pertains to ensuring everyone should be given a chance to be selected?

Sampling procedure, Sample size, and Participation (response)

What three factors influence sample representativeness?

You can detect a possible bias

What action can be taken if participants refuse to respond and there is a common reason related to the variable being measured?

Household heads with higher educational attainment

In Case #1 (Educational Attainment), which group of household heads would likely be missed if surveying on a weekday?

They might be working

In Case #1, what is the likely reason why household heads with higher educational attainment would result in non-response on a weekday?

Document why they refuse to participate

What must researchers do regarding refusal to participate to explain possible biases in selection?

When your population is very small

What is one instance when you might sample the entire population?

Less than 200 houses

What approximate size of a community led the lecturer to resort to total enumeration?

When you have extensive resources

What is one instance when you might sample the entire population, especially if you are conducting a census?

When you don’t expect a very high response

What is one instance when sampling the entire population might be chosen, although it will end up with biases?

Theoretical Population

In sampling terminology, what refers to who you want to generalize to?

Study Population

In sampling terminology, what refers to the population you can get access to?

Sampling Frame

In sampling terminology, what refers to how you can get access to the population?

Sample

In sampling terminology, what refers to who is in your study?

The target population

In statistical inference, what population do researchers aim to generalize a particular measurement to?

NCR (Metro Manila)

In the example of measuring obesity in the Philippines, what might the sample be narrowed down to if the entire Philippine population is inaccessible?

Sampling frame

What is needed to be somehow ensured that the study population is complete and everyone is given a chance to be selected?

A large, but not complete, overlap

Due to sampling frame issues, what overlap usually exists between the target population and the sample?

Logistical issues

What commonly prevents the ideal overlap between the target population and the sample from being achieved?

Study rats to understand human health

What is an example where the study population and the population about which information is desired may be entirely separate?

We seek a sampling frame

What remedy is sought when it is impossible to identify and measure every single item in a general population?

Probability sampling/samples and Non-probability sampling/samples

What are the two types of samples?

Everyone in the population is given a chance (greater than zero percent) to be selected in the process or procedure, and this probability can be accurately determined

What is a Probability sampling scheme?

Simple random sampling, Systematic random sampling, Stratified random sampling, Multistage sampling, Multiphase sampling, and Cluster sampling

What are six examples of Probability sampling methods?

Not all were given the chance or probability to be selected

What defines Non-Probability Samples?

Convenience sample, Purposive sample, and Quota

What are three examples of Non-Probability sampling methods?

A sampling frame

What is needed to ensure that everybody gets a chance in a complex population like the Philippines?

Regions, provinces, cities/municipalities, districts, barangays, households

What organizational layers are assessed below the national level in the Philippines for sampling purposes (Case #2)?

Multistage sampling design

What type of sampling design is needed to ensure everyone is given a chance in a complex, layered population structure like the Philippines (Case #2)?

Defining the population of concern

What is considered the first step in the sampling process?

Reviewing the sampling process

What is the final step in the sampling process?

Sample size computation

What activity is performed during the determining the sample size stage of the sampling process?

To find a representative sample (or subset) of that population

What is the goal of population sampling due to time or money constraints?

This pertains to the objective of the sampling frame

What concept is related to the ideal scenario where the study population is complete in the list and everyone is given a chance?

The sampling frame must be representative of the population

What property must the sampling frame possess?

Equal Probability of Selection (EPS) design

What is the term when every element in the population has the same probability of selection?

Self-weighting

What term are EPS designs also referred to as?

Simple random sampling

What is an example of an EPS design where all units have an equal chance of selection (Case #3)?

Assigning a number to each person or name

What procedure is performed in Simple Random Sampling after listing everyone (Case #3)?

Microsoft Excel or Google Sheets, a table of random numbers, or draw lots (lottery)

What three methods can be used to generate random samples for SRS?

Microsoft Excel or Google Sheets

What is the most efficient method now for generating random samples?

The organization of the population is simple

When is Simple Random Sampling applicable?

When some elements of the population have no chance of selection

What defines Non-Probability Sampling?

Out of coverage or undercovered population

What are two terms used to describe populations that researchers cannot access or deliberately exclude in non-probability sampling?

Cannot be accurately determined

What is true about the probability of selection in non-probability sampling?

Assumptions regarding the population of interest

What is the selection of elements based on in non-probability sampling?

Does not allow the estimation of sampling errors

What statistical limitation does non-probability sampling have?

You have inferential statistics in mind

In what scenario is non-probability sampling not applicable?

Non-probability sample

If you visit a street and interview the first person to answer the door in any household with more than one occupant, what type of sample is this?

Convenience

What type of non-probability sampling is involved if selecting those who answer the door and excluding others in the household?

Inferential statistics will be ignored or criticized

What happens to inferential statistics if probability sampling was not carried out?

Bias could occur

What is a risk related to data quality when using online surveys?

Accidental sampling

What type of non-probability sampling is based purely on chance or "by accident"?

Quota sampling

What type of non-probability sampling stops when a predetermined number or proportion of units is met?

Purposive sampling

What type of non-probability sampling involves judgment and selection due to certain characteristics?

Qualitative

What type of research commonly uses purposive sampling?

Nonresponse effects

What may turn any probability design into a nonprobability design if the characteristics of nonresponse are not well-understood?

Increase the sample size

What must be done to provide an allowance for nonresponse when computing for sample size?

20%

What nonresponse rate was used in the example requiring increasing a sample size of 100 to 120?

Selection bias

What may capturing the reason for refusal or failure to obtain a response help mitigate?

Small, homogeneous, and readily available

What three conditions make Simple Random Sampling (SRS) applicable?

Less than 1000

What is the approximate size of a 'small' population where SRS is applicable?

All subsets of the frame are given an equal probability

What statement defines the probability of subsets in SRS?

It provides for the greatest number of possible samples

What is a key feature of SRS regarding possible samples?

Easy to calculate

How are the estimates derived from SRS described?

The sampling frame is too large

What is one disadvantage that makes SRS impracticable (e.g., a national survey of 110 million Filipinos)?

Clustering by provinces or municipalities

What alternative method is more appropriate than SRS for a national survey of 110 million Filipinos?

Minority subgroups of interest in the population may not be present in the sample in sufficient numbers for the study

What issue might SRS present regarding subgroups?

Data privacy

What institutional issue prevented the lecturer from obtaining a hospital list for NCD research?

Convenience sampling

What non-probability method did the lecturer resort to due to circumstances like data privacy refusal?

Descriptive study

What did the lecturer's research become due to the inability to validate probability sampling and the resulting bias?

Sampling without replacement (WOR)

What type of sampling scheme means no element can be selected more than once in the same sample?

Sampling with replacement (WR)

What type of sampling scheme means an element may appear multiple times in one sample?

Sampling Without Replacement (WOR)

Which type of sampling (WR or WOR) is preferred for studies?

Better to increase the sample size from the beginning to cover the non-response

What is the suggested action regarding sample size if many potential subjects refuse to participate?

Multiphase sampling

Which probability sampling method is an example that is NOT non-probability sampling?

Homogeneous

What characteristic of the population is described as 'nearly the same' in the context of SRS applicability?

Systematic sampling

What type of probability sampling relies on arranging the target population according to some ordering scheme and then selecting elements at regular intervals?

A random start and then proceeds with the selection of every Kth element from then onwards

What two elements define the selection process in systematic sampling?

K = population size/sample size

What is the formula for K (the interval) in systematic sampling?

From within the first to the Kth element on the list

Where is the starting point randomly chosen in systematic sampling?

To ensure that the sampling is evenly spread throughout the sampling frame

What is the primary purpose of systematic sampling?

It allows researchers to sweep through all 200 students, ensuring even distribution

Why is systematic random sampling preferred over SRS when sampling 20 out of 200 students with potential clustering issues?

It can cover the whole geography of the community

What advantage does systematic random sampling offer in community surveys where a map might not be available (e.g., households in a barangay)?

VI → IV → II → III → V → VII → I

What is the correct sequence of the seven stages of the sampling process?

To determine if the confidence interval is very high or not depending on the sample size that we have

What is the known accuracy of results used to determine in relation to confidence intervals?

Sampling frame

What is the list from which potential respondents are drawn?

Community map or patient listings

What are two examples of sampling frames?

Probability

What type of sampling requires assessing the sampling frame in terms of completeness and being up-to-date?

Nonresponse effects

What term describes the potential for a probability design to turn into a nonprobability design if characteristics are misunderstood?

Modifies each element’s probability of being sampled

What is the effect of nonresponse on the element's probability?

To ensure sufficient participation

Why is the sample size increased to account for nonresponse rate?