Statistics: Random Sampling Methods

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Questions and Answers

What is the primary purpose of stratified random sampling?

To increase the sample size by combining multiple strata

To ensure equal representation of all strata in the sample

To reduce bias in the sample by dividing the population into homogeneous groups (correct)

To simplify the sampling process by using a single stratum

What is a characteristic of systematic random sampling?

The sample is drawn from a list of the entire population

The sample is divided into strata based on specific attributes

Every individual in the population has an equal chance of being selected

The first individual is randomly chosen, followed by every nth individual (correct)

What is the main advantage of stratified random sampling?

It provides accurate data when the distribution of the variable is not uniform (correct)

It reduces the cost of sampling

It increases the sample size

It simplifies the data analysis process

What is cluster sampling used for?

To study a subset of the population, such as schoolchildren or industrial workers Signup and view all the answers

What is multi-stage random sampling used for?

To study a widespread population, such as in national studies Signup and view all the answers

What is the primary goal of simple random sampling?

To give every individual in the population an equal chance of being selected Signup and view all the answers

What is the main difference between simple random sampling and stratified random sampling?

The method of selecting the sample Signup and view all the answers

What is the advantage of using multiple sampling techniques?

It allows for more accurate representation of the population Signup and view all the answers

What is the primary purpose of sampling in clinical research?

To save time, effort, and money while gathering required data Signup and view all the answers

What determines the sample size in a research study?

The available resources and facilities Signup and view all the answers

What is a characteristic of a simple random sample?

Every individual in the population has an equal chance of appearing in the sample Signup and view all the answers

What is the purpose of providing sufficient details in a research methodology?

To replicate and validate the study Signup and view all the answers

What is the target population in clinical research?

The wider group to which the research might apply Signup and view all the answers

What is an advantage of sampling in clinical research?

It decreases possible errors Signup and view all the answers

What is a type of random sample?

Simple random sample Signup and view all the answers

What is the order of sampling in a multi-stage sampling design?

Governorates, cities, districts, villages, families and individuals Signup and view all the answers

What is important to ensure when selecting a sample in clinical research?

The sample is representative of the population Signup and view all the answers

What type of sampling is chosen based on the investigator's own judgment and experience?

Non-random sampling Signup and view all the answers

What is the primary goal of using primary data collection?

To collect data directly from respondents Signup and view all the answers

Which type of sampling is biased because it gives people with more social connections a higher chance of selection?

Snowball sampling Signup and view all the answers

What is the main limitation of non-random sampling?

The results cannot be generalized to the whole population Signup and view all the answers

What is the purpose of using judgmental sampling?

To select participants with expertise in the area being researched Signup and view all the answers

What is the advantage of using snowball sampling?

It leads to higher response rates Signup and view all the answers

What is the primary difference between primary and secondary data collection?

Primary data collection involves collecting data directly from respondents Signup and view all the answers

Study Notes

Random Sampling

In simple random sampling, the target population is listed from A to Z, and then a required sample is selected using computer software, random number generator, or randomization tables.
Stratified random sampling involves dividing the target population into homogeneous groups (strata) based on attributes and variables like age, sex, occupation, and socioeconomic status, and then drawing a random sample from each stratum.
Systematic random sampling involves numbering houses or individuals, selecting the first one randomly, and then every nth one (e.g., 5th, 10th, or 15th) to achieve the desired sample size.
Cluster sampling involves identifying clusters (confined groups) like schoolchildren, industrial workers, or households, and then selecting certain clusters using simple random sampling.

Non-Random Sampling

Non-random sampling involves choosing a sample based on the investigator's own judgment and experience, and the results cannot be generalized to the whole population.
Convenience sampling involves selecting members of the population based on their ease of access, which can lead to biased samples.
Snowball sampling involves reaching inaccessible populations by asking the first respondent to refer an acquaintance, and then the friend refers another, and so on.
Judgmental sampling or purposive sampling involves choosing the sample based on the researcher's judgment of who would be appropriate for the study.

Data Collection

Data can be obtained through research work and survey studies.
There are two types of data collection: primary data collection, where data is collected directly by the investigator or colleagues, and secondary data collection.

Research Methodology

Research methodology involves describing the research design, methods, and procedures used to collect and analyze data.
It includes information on sample size, data sources, data collection tools, and data analysis techniques.
It provides sufficient details for replication and validation of the study.

Sampling

In clinical research, a sample is used to represent a wider group, known as the target population.
Advantages of sampling include saving time, effort, and money, while giving the required data, and allowing fulfillment of work with limited resources.
Sampling can decrease possible errors.

Sample Size

There is no fixed size of sample, and it varies according to certain determining factors like available resources and facilities, expected variability in the characteristics under study, prevalence of the disease or problem, and variability of the group.

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Description

This quiz covers different methods of random sampling, including simple random sampling and stratified random sampling, used in research to select a representative sample from a target population.