Module 7.1 : Sampling Techniques & Central Limit Theorem Flashcards
(24 cards)
What is probability sampling?
Selecting a sample when we know the probability of each sample member in the overall population.
What is simple random sampling?
A method where each item in the population has the same likelihood of being included in the sample.
How is simple random sampling typically performed?
By numbering items, placing them in a hat, and drawing randomly.
What is systematic sampling?
Selecting every nth member from a population.
What does stratified random sampling involve?
Separating the population into smaller groups based on distinguishing characteristics and taking random samples from each.
What is the purpose of stratified sampling in bond indexing?
To categorize bonds based on risk factors and draw samples from each category.
In stratified sampling, how is the size of samples determined?
Based on the size of the stratum relative to the population.
What is cluster sampling?
Sampling based on subsets of a population, assuming each cluster is representative of the overall population.
What is the difference between one-stage and two-stage cluster sampling?
One-stage selects entire clusters; two-stage selects random samples from within selected clusters.
What are the primary advantages of cluster sampling?
Lower cost and less time required to assemble the sample.
What is convenience sampling?
Selecting sample data based on ease of access.
What is judgmental sampling?
Samples selected based on the researcher’s experience and judgment.
What is a key consideration when sampling regarding data distribution?
Ensuring the distribution of data of interest is constant for the whole population.
What does the central limit theorem state?
The sampling distribution of the sample mean approaches a normal distribution as sample size increases.
What is the significance of the sample size n in the central limit theorem?
If n ≥ 30, the sampling distribution of sample means will be approximately normal.
What is the relationship between the population mean and the mean of the distribution of sample means?
They are equal.
What is the standard error of the sample mean?
The standard deviation of the distribution of sample means.
What is the jackknife method?
A resampling method that calculates multiple sample means by removing one observation at a time.
What is the bootstrap method?
A resampling method that draws repeated samples from the full dataset to estimate the standard error.
What is an advantage of the bootstrap method?
It can improve accuracy and construct confidence intervals for various statistics.
Fill in the blank: The central limit theorem is useful for hypothesis testing and constructing _______.
confidence intervals.
True or False: Cluster sampling generally has lower sampling error than simple random sampling.
False.
What is the formula for standard error of the sample mean?
The bootstrap method improves accuracy compared to only using the data in _______.
A single sample
