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Questions and Answers
What is the definition of a sample?
What is the definition of a parameter?
What is the definition of a statistic?
What is the definition of a sampling frame?
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What is the definition of a variable?
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What is the definition of sample size?
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What is the sampling interval if you have a school with 1000 students and you want to select a sample of 100 students?
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When using systematic sampling, if the starting point selected is number 5, which student will be included in the sample after the 5th student?
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In stratified sampling, why is the population divided into different subgroups or strata?
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What is the purpose of determining the sample size for each stratum in stratified sampling?
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In systematic sampling within each stratum during stratified sampling, how are samples selected?
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Why is stratified sampling beneficial when a university wants to survey students about campus services?
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What sampling technique involves dividing the population into strata based on certain characteristics?
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In stratified sampling, how does the university decide on the proportion of each group to include in the sample?
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Which non-random sampling method relies on existing study subjects recruiting future subjects from their acquaintances?
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When is cluster sampling often used as a sampling method?
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What is the main concern with convenience sampling?
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Which method of non-random sampling relies on the researcher's judgment to select individuals considered representative of the population?
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What is the main advantage of collecting primary data?
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What is the first step in systematic sampling?
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Which of the following is NOT a method for collecting primary data?
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What is the formula used to calculate the interval (k) in systematic sampling?
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Which of the following is a disadvantage of collecting primary data?
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What is the purpose of systematic sampling?
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Which of the following is the variable that is manipulated or varied in an experiment?
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If the number of hours spent studying per day is the independent variable, what would be the dependent variable?
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Which of the following is an example of a continuous variable?
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What type of variable is 'eye color'?
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If a variable measures the level of satisfaction on a scale from 1 to 5, what type of variable is it?
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What is the main difference between quantitative and qualitative variables?
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Study Notes
Data Collection
- Primary data is collected at the source, using methods such as surveys, interviews, focus groups, observations, and experiments.
- Primary data is more relevant to the specific research question because it is collected with the research design and data requirements in mind.
- However, collecting primary data can be more time-consuming, costly, and requires more resources than using secondary data.
Systematic Sampling
- Systematic sampling involves selecting members at regular intervals through an ordered list.
- This type of sampling is often used when a complete list of all members of the population is available.
- The steps to conduct systematic sampling are:
- Determine the sample size
- Calculate the interval (k) by dividing the size of the entire population (N) by the desired sample size (n)
- Select the starting point randomly between 1 and k
- Select the sample by starting from the randomly chosen point and selecting every k-th member of the population
Variables
- There are two main types of variables in statistics: independent variable (explanatory variable) and dependent variable (response variable).
- Independent variable is the variable that is manipulated or varied in an experiment to explore its effect on a dependent variable.
- Dependent variable is the outcome or response that is measured to see if it is affected by changes in the independent variable.
- Examples of independent and dependent variables include:
- Number of hours spent studying per day and scores on a math test
- Duration of exercise per week and heart rate or cholesterol levels in participants
- Variables can be classified into:
- Quantitative variables (discrete and continuous)
- Qualitative variables (nominal and ordinal)
Measurements
- A sample is a sub-collection of elements drawn from a population.
- Sampling is the process of selecting a subset of data from the population.
- Parameter is a descriptive measure (value) computed from the population.
- Statistic is a measure used to describe the sample.
- Examples of parameters and statistics include:
- Population mean and population standard deviation
- Sample mean and sample standard deviation
Data Sources
- Data sources can be classified into:
- Historical sources (secondary sources)
- Field sources (primary sources)
- Historical sources include:
- Books
- Journal articles
- Reports
- Census data
- Historical records
- Data sets that are publicly available
- Field sources include:
- Primary data collected firsthand specifically for the research objectives
Stratified Sampling
- Stratified sampling is a method of sampling from a population in which the population is divided into different subgroups or strata that share similar characteristics.
- Samples are then drawn from each stratum to ensure representation of all groups within the population.
- The steps to conduct stratified sampling are:
- Divide the population into strata based on a shared attribute or characteristic
- Determine the sample size for each stratum
- Select the sample from each stratum using random sampling or systematic sampling
Cluster Sampling
- Cluster sampling involves dividing the entire population into clusters (groups), and a random sample of these clusters is chosen.
- All individuals within the selected clusters are then studied.
- This method is often used when the population is spread over a wide area.
Non-Random Sampling
- Non-random sampling methods include:
- Convenience sampling: selecting individuals who are easiest to reach
- Judgmental or purposive sampling: selecting individuals who are considered to be representative of the population
- Quota sampling: selecting individuals to meet specific quotas
- Snowball sampling: existing study subjects recruit future subjects from among their acquaintances
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Description
Learn about sampling, parameters, and statistics in statistics. Understand the difference between parameters, which describe the entire population, and statistics, which describe the sample. Explore how sampling is the process of selecting a subset of data from a population.
