Podcast
Questions and Answers
Which of the following types of probability samples involves selecting participants at regular intervals from a sorted list?
Which of the following types of probability samples involves selecting participants at regular intervals from a sorted list?
What is a characteristic of non-probability sampling?
What is a characteristic of non-probability sampling?
What type of probability sample divides the population into subgroups and then randomly selects samples from each subgroup?
What type of probability sample divides the population into subgroups and then randomly selects samples from each subgroup?
Which sampling method uses a two or more stage process to select samples?
Which sampling method uses a two or more stage process to select samples?
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Which sampling method is NOT considered a non-probability sampling technique?
Which sampling method is NOT considered a non-probability sampling technique?
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Which of the following statements correctly defines purposive sampling?
Which of the following statements correctly defines purposive sampling?
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In which type of probability sampling are entire groups or clusters randomly selected, and then all or some individuals from those groups are studied?
In which type of probability sampling are entire groups or clusters randomly selected, and then all or some individuals from those groups are studied?
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In which scenario would non-probability sampling be the preferred choice?
In which scenario would non-probability sampling be the preferred choice?
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Which sampling method ensures that every individual in the population has an equal chance of being selected?
Which sampling method ensures that every individual in the population has an equal chance of being selected?
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What is a potential drawback of using non-probability sampling methods?
What is a potential drawback of using non-probability sampling methods?
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What is one of the primary conditions for creating strata in a population?
What is one of the primary conditions for creating strata in a population?
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What does stratification help ensure regarding minority subgroups?
What does stratification help ensure regarding minority subgroups?
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Which of the following is NOT a goal of stratification?
Which of the following is NOT a goal of stratification?
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In stratification, what is the significance of having homogeneous strata?
In stratification, what is the significance of having homogeneous strata?
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How can stratification be implemented effectively?
How can stratification be implemented effectively?
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What is an advantage of using stratified sampling?
What is an advantage of using stratified sampling?
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Why is it beneficial to use the same sampling fraction for all strata in stratified sampling?
Why is it beneficial to use the same sampling fraction for all strata in stratified sampling?
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What is one limitation of stratified sampling compared to other methods?
What is one limitation of stratified sampling compared to other methods?
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How does stratified sampling enhance the quality of the research findings?
How does stratified sampling enhance the quality of the research findings?
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Which statement is not true about the advantages of stratified sampling?
Which statement is not true about the advantages of stratified sampling?
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What must be prepared separately for each stratum when creating a sampling frame?
What must be prepared separately for each stratum when creating a sampling frame?
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What issue arises when examining multiple criteria in stratified designs?
What issue arises when examining multiple criteria in stratified designs?
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How can the design of stratified sampling potentially be hindered?
How can the design of stratified sampling potentially be hindered?
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Why can the utility of created strata be reduced?
Why can the utility of created strata be reduced?
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What is a potential consequence of having poorly defined stratifying variables?
What is a potential consequence of having poorly defined stratifying variables?
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What defines a cluster sample in the context of multistage random sampling?
What defines a cluster sample in the context of multistage random sampling?
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Which situation best exemplifies a cluster sampling scenario?
Which situation best exemplifies a cluster sampling scenario?
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In cluster sampling, what is meant by 'en toto'?
In cluster sampling, what is meant by 'en toto'?
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Which of the following is NOT a characteristic of cluster sampling?
Which of the following is NOT a characteristic of cluster sampling?
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What is a potential benefit of using cluster sampling in research?
What is a potential benefit of using cluster sampling in research?
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Study Notes
Sampling Techniques
- A sample is a part of a population, selected to represent the population's variables.
- Sampling is essential in research as comprehensive studies are often impractical.
Advantages of Sampling
- Lower cost than comprehensive surveys
- Faster data collection
- Potentially richer information
- Necessary when a comprehensive survey is impossible (e.g., studying fish, animals, or nomadic populations, quality control of industrial products, examining patient blood)
Types of Sampling
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I. Non-Probability (Non-Random) Samples
- a. Purposive samples: Chosen based on judgment; results cannot be generalized.
- b. Pre-test or pilot study: Used to test studies, identifying crucial parameters and eliminating unnecessary variables.
- c. Quota sample: Used (e.g., in U.S.A. by Gallup Institute prior to voting) to gather information from a specific number of individuals in different groups; not used in community medicine or clinical practice.
- d. Convenience sample: Made up of people easy to reach, a common type of non-probability sampling.
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II. Probability (Random) Samples
- Characteristics: Selection probability is determined; standard error calculated; results can be generalized.
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Types:
- Simple random sample
- Systematic random sample
- Stratified random sample
- Multistage random sample
- Cluster sample
Simple Random Sample
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Methods:
- Selection from a frame of equal-sized papers labeled with serial numbers from the population. Papers are mixed, and desired number are chosen.
- Coin tossing
- Selecting random balls from a container.
- Generating random numbers via computer
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Advantages:
- Basic type of probability sampling
- Every population member has an equal chance of selection
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Disadvantages:
- Frame construction can be difficult for large populations.
- Sample members may be concentrated in one population segment (e.g., only females).
- Not suitable for populations with high variability.
Systematic Random Sample
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Methods: Selects every 'kth' member from the population list, starting from a randomly selected point (e.g., if k = 10 and the random starting point is 4, the sequence is 4, 14, 24, 34...).
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Advantages:
- Easy to select
- Well-distributed throughout the population.
- More precise than simple random sampling.
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Disadvantages:
- Difficulty is constructing the frame for large populations.
- Possible unequal selection probabilities if population listing has a periodic pattern.
Stratified Random Sample
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Characteristics: The population is divided into multiple homogenous strata (e.g., based on education level, occupation, socioeconomic status). A random sample is selected from each stratum in proportion to its size in the population.
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Advantages:
- Each unit has an equal chance of selection
- Proportional representation in the sample.
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Disadvantages:
- Requires a sampling frame for each stratum.
- Complicated stratification of multiple variables.
Multistage Random Sample
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Methodology: Sampling of units occurs at multiple levels (e.g., selecting governorates, districts, talukas, and then villages as the final units to interview).
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Advantages:
- Easy to construct the frame.
- Efficient for very large populations.
- Cost-effective (travel and administrative costs).
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Disadvantages:
- May not be as precise as simpler sampling methods if the sample size is the same.
Cluster Sampling
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Characteristics: Population divided into clusters, then a random sample of clusters is selected. All individuals within the selected clusters are sampled.
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Advantages:
- Cost savings in preparing sampling frames.
- Reduces travel and administrative costs.
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Disadvantages:
- Higher sampling errors compared to other random sampling methods.
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Description
Test your knowledge of various sampling methods in statistics with this quiz. Delve into probability and non-probability sampling techniques, their characteristics, and when each method is best applied. Perfect for students studying statistics or research methodologies.
