26 Questions
What is the main purpose of sampling in research?
To ensure the sample represents the population
Which term refers to all individuals or lab specimens in which the study results are expected to extrapolate to?
Population
Why is selecting a representative sample essential in research?
To draw accurate conclusions about the population
What is the definition of a 'sample' in the context of research?
A subset of the population that is studied
Which stage of research involves developing a specific question or hypothesis?
Research Terminology
Why is it impossible to study every individual in a population of interest?
Because only a subset can be studied effectively
In stratified sampling, what is the primary difference between proportionate and disproportionate sampling?
Equal probability of selection across strata in proportionate sampling.
What is the key characteristic of cluster sampling?
Recruiting all or some participants within chosen clusters.
Which type of sampling is most appropriate when a 'truly random' sample cannot be obtained due to unavailable sampling frame?
Convenience sampling
What makes snowball sampling different from other non-probability methods?
Participants recruit more participants themselves.
Which type of bias refers to a systematic tendency to include/exclude certain groups in a sample?
Selection bias
What is the main disadvantage associated with snowball sampling?
Relatively subjective nature of the method.
How does quota sampling differ from stratified sampling?
'Truly random' sample selection in stratified sampling.
'Sampling methods – probability sampling' is classified into how many categories?
3
'Sampling methods – non-probability sampling' is particularly useful when:
'Truly random' samples are not possible to obtain.
'Purposive sampling' differs from convenience and quota sampling by focusing on:
'Experiences or knowledge of a topic.'
What is bias in research?
Unexpected, systematic variation in a research finding
In the context of pharmaceutical testing, what does the term 'API' refer to?
Active Pharmaceutical Ingredient
Why is it important to estimate sample size in a research study?
To ensure a large sample for better generalizability
What is the main difference between cross-over study designs and parallel designs in terms of required sample size?
Cross-over designs require a larger sample size
Which sampling method involves selecting every nth participant or specimen from a list?
Systematic sampling
What advantage does systematic sampling have over simple random sampling?
Simpler and easier to implement
'Stratified random sampling' involves dividing the population into what?
Subgroups or strata
'Power' in research refers to the likelihood of what?
Rejecting the null hypothesis when there is one
'Response rates' in research refer to what?
'Estimated percentage of participation from the available sample'
In simple random sampling, what does each unit (participant, specimen, material) have?
Equal chance or probability of being selected
Study Notes
Research Methods
- Research involves identifying the need for research, developing a research question or hypothesis, identifying appropriate methods to conduct the research, and sampling.
Definition of Terms
- Population: All individuals or lab specimens in which we are interested and to which we want the study results to extrapolate.
- Sample: A subset of the population that we are able to study, which is representative of the population.
Sampling
- Sampling: The way in which we collect data from the population under study, aiming to ensure the sample is representative of the population.
- Importance of sampling: Selecting the sample is key to the conclusions we draw and the resulting decisions.
Types of Sampling
-
Probability Sampling: Involves random selection of samples, aiming for objectivity and minimizing bias.
- Simple Random Sampling: Each unit has an equal chance of being selected, requiring a complete list of the population (sampling frame).
- Systematic Sampling: Selection of every nth participant or specimen, where n = total population / target sample size.
- Stratified Random Sampling: Dividing the population into subgroups (strata) and selecting a random sample from each stratum.
-
Non-Probability Sampling: Useful when a truly random sample is not possible, e.g., no sampling frame can be found or constructed.
- Convenience Sampling: Selecting participants based on availability or researcher's convenience.
- Quota Sampling: A form of stratified sampling, except with non-random selection of participants.
- Snowball Sampling: Recruiting participants from a small, inaccessible population, using a small convenient sample to recruit more participants.
- Purposive Sampling: Selecting participants based on their experiences or knowledge of a topic, commonly used in qualitative research.
Sampling Bias
-
Types of Sampling Bias:
- Selection Bias: Systematic tendency to include/exclude individuals or groups in the sample.
- Non-Response Bias: Occurs when there is a significant difference between those who participated and those who did not participate in a study.
- Volunteer Bias: Participants who chose to participate in research may have a particular interest or issue with the subject of study.
Application of Sampling
- Pharmaceutical Testing: Sampling plans are used to assess the quality of medicinal products on the market, ensuring the API is evenly spread throughout the blend.
- Sampling Methods: Considering sample size, randomized or non-randomized methods, and factors to consider when estimating sample size, such as study design, data collection procedures, response rates, effect size, and power.
Sample Size Estimation
- Importance of Sample Size Estimation: Planning and allocating resources to conduct research, ensuring that any differences observed in the sample are true.
- Factors to Consider: Study design, data collection procedures, response rates, effect size, and power.
Learn about sampling techniques commonly used in research, such as probability and non-probability sampling. Identify types of sampling bias and understand the importance of sampling in research. Develop research questions, conduct literature reviews, and analyze data to disseminate findings effectively.
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