Kundali IQHome › Exam notes › UGC NET › Sampling
Sampling
Research Skills
Useful for: UGC NET, CSIR NET, Central Univ./IIT/NIT Faculty, OPSC Assistant Professor, OPSC PGT, OSSC Art Education Instructor, OSSC Economics, OSSC English
Overview
Inference uses sample data to estimate population values and to test hypotheses with known error probabilities.
Key points
- Sampling: simple random, stratified, systematic, cluster, multi-stage.
- Standard error of the mean = σ/√n.
- 95% confidence interval for the mean (large sample) = x̄ ± 1.96 σ/√n.
- Type I error: rejecting a true null (probability α); Type II: accepting a false null (probability β).
- Z-test for large samples or known σ; t-test for small samples with unknown σ; χ² for frequencies and independence.
Explanation
- Power of a test = 1 − β.
- Larger samples give smaller standard errors and narrower intervals.
- Degrees of freedom for a one-sample t-test = n − 1.
- A p-value below α leads to rejecting the null hypothesis.
Step by step
- Identify the measure or test asked and its formula.
- Organise the data (table, totals) before computing.
- Interpret the result (sign, size, significance).
Examples
- Σ = 10, n = 100 → standard error = 1.
- X̄ = 50, σ = 10, n = 100 → 95% CI = 50 ± 1.96 = 48.04 to 51.96.
- Probability of a Type I error equals the significance level α.
Traps and advanced points
- Trap: Using σ instead of σ/√n.
- Trap: Confusing Type I and Type II errors.
- Trap: Using a z-test for a small sample with unknown σ.
Quick revision
- SE = σ/√n.
- X̄ ± 1.96 SE.
- Α = Type I.
Practice MCQs
During a research-methods workshop on Sampling, the team checks the design before collecting evidence. which statement about Sampling is NOT appropriate?
- A sample should be selected using a method appropriate to the population and inference intended.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be interpreted according to its purpose and context.
- A very large convenience sample is automatically representative.
Read chapter notes · Similar questions
Show answer
Answer: (d) A very large convenience sample is automatically representative.. The NOT-appropriate statement is: A very large convenience sample is automatically representative.
Snowball sampling is most suitable for studying —
- a school with full lists
- hidden or hard-to-reach groups
- the national census
- laboratory samples
Read chapter notes · Similar questions
Show answer
Answer: (b) hidden or hard-to-reach groups. Each participant refers others.
A sample in research is —
- the whole population
- a part of the population selected for study
- a research tool
- the final result
Read chapter notes · Similar questions
Show answer
Answer: (b) a part of the population selected for study. A sample represents the population.
Choose the most defensible exam-ready conclusion about Sampling.
- A sample should be selected using a method appropriate to the population and inference intended.
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (a) A sample should be selected using a method appropriate to the population and inference intended.. Choose the most defensible exam-ready conclusion about Sampling.: A sample should be selected using a method appropriate to the population and inference intended.
Which statement about Sampling is NOT appropriate?
- A sample should be selected using a method appropriate to the population and inference intended.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be interpreted according to its purpose and context.
- A very large convenience sample is automatically representative.
Read chapter notes · Similar questions
Show answer
Answer: (d) A very large convenience sample is automatically representative.. The NOT-appropriate statement is: A very large convenience sample is automatically representative.
While reviewing a study proposal on Sampling, the team checks the design before collecting evidence. which statement about Sampling is NOT appropriate?
- A sample should be selected using a method appropriate to the population and inference intended.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be interpreted according to its purpose and context.
- A very large convenience sample is automatically representative.
Read chapter notes · Similar questions
Show answer
Answer: (d) A very large convenience sample is automatically representative.. The NOT-appropriate statement is: A very large convenience sample is automatically representative.
The population is divided into subgroups and a random sample is drawn from each. This is —
- stratified sampling
- snowball sampling
- convenience sampling
- purposive sampling
Read chapter notes · Similar questions
Show answer
Answer: (a) stratified sampling. Strata ensure every subgroup is represented.
A teacher wants to apply Sampling correctly. Which action is most appropriate?
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (c) Match probability/non-probability sampling to the study purpose and claims.. A sample should be selected using a method appropriate to the population and inference intended.
After a random start, a researcher picks every 10th name from a list. This is —
- simple random sampling
- systematic sampling
- cluster sampling
- quota sampling
Read chapter notes · Similar questions
Show answer
Answer: (b) systematic sampling. A fixed interval after a random start = systematic sampling.
While planning a small research study on Sampling, the team checks the design before collecting evidence. which statement about Sampling is NOT appropriate?
- A sample should be selected using a method appropriate to the population and inference intended.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be interpreted according to its purpose and context.
- A very large convenience sample is automatically representative.
Read chapter notes · Similar questions
Show answer
Answer: (d) A very large convenience sample is automatically representative.. The NOT-appropriate statement is: A very large convenience sample is automatically representative.
While planning a small research study on Sampling, the team checks the design before collecting evidence. A teacher wants to apply Sampling correctly. Which action is most appropriate?
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (c) Match probability/non-probability sampling to the study purpose and claims.. A sample should be selected using a method appropriate to the population and inference intended.
While planning a small research study on Sampling, the team checks the design before collecting evidence. Choose the most defensible exam-ready conclusion about Sampling.
- A sample should be selected using a method appropriate to the population and inference intended.
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (a) A sample should be selected using a method appropriate to the population and inference intended.. A sample should be selected using a method appropriate to the population and inference intended.
During a research-methods workshop on Sampling, the team checks the design before collecting evidence. A teacher wants to apply Sampling correctly. Which action is most appropriate?
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (c) Match probability/non-probability sampling to the study purpose and claims.. A sample should be selected using a method appropriate to the population and inference intended.
During a research-methods workshop on Sampling, the team checks the design before collecting evidence. Choose the most defensible exam-ready conclusion about Sampling.
- A sample should be selected using a method appropriate to the population and inference intended.
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (a) A sample should be selected using a method appropriate to the population and inference intended.. A sample should be selected using a method appropriate to the population and inference intended.
While reviewing a study proposal on Sampling, the team checks the design before collecting evidence. A teacher wants to apply Sampling correctly. Which action is most appropriate?
- A very large convenience sample is automatically representative.
- Sampling is useful only for record keeping and has no effect on learning.
- Match probability/non-probability sampling to the study purpose and claims.
- Sampling should be applied identically in every situation without checking learner needs.
Read chapter notes · Similar questions
Show answer
Answer: (c) Match probability/non-probability sampling to the study purpose and claims.. A sample should be selected using a method appropriate to the population and inference intended.
More topics in this chapter
Notes and questions are written by Kundali IQ for practice. They are not official papers; always check the latest official notification for the syllabus and pattern.