Given below are two statements:
Statement I: When selection procedure is biased, taking a large sample will help reduce the bias.
Statement II: In a normally distributed data, the chances of individual observed values deviating more than 3 times the standard deviation from the mean value, are very less.
In the light of the above statements, choose the most appropriate answer from the options given below:
Statement I is incorrect but Statement II is correct
This question contrasts two ideas from sampling theory and the normal distribution.
Statement I is incorrect. A biased selection procedure produces systematic error, not random error. If the method itself favours certain units — say it systematically over-samples urban voters — then enlarging the sample simply pulls in more of the same skewed units. The distortion does not average out; it stays baked in and can even make the wrong estimate look more precise (a tighter confidence interval around a biased value). Sample size only reduces random sampling error (variance). To remove bias one must fix the selection mechanism itself — for example by using proper randomisation or correcting the sampling frame. Hence the claim that a large sample cures selection bias is wrong.
Statement II is correct. In a normal distribution the empirical (68–95–99.7) rule tells us that about 99.7% of all values lie within ±3 standard deviations of the mean. Consequently only about 0.3% of observations fall beyond ±3 standard deviations — roughly 3 in 1000. So the chance of an individual value deviating from the mean by more than three standard deviations is genuinely very small, exactly as the statement asserts.
Since the first statement fails and the second holds, the answer is Statement I is incorrect but Statement II is correct.
Similar Questions
Given below are two statements :
Statement I : In probability sampling, it is not necessary that all the members of population have an equal opportunity to be the part of the sample.
Statement II : Non probability sampling method is not a fixed or predefined selection process.
In the light of the above statements, choose the correct answer from the options given below :
A sample of respondents which is available to researchers because of their access to the respondents is identified as :
In online surveys, which of the following are sampling issues ?
A. People in a household may use the same computer, as they have access to only one.
B. Many respondents may have multiple email IDS.
C. Internet users constitute a biased sample of the population
D. Sampling frames for online surveys are cheap.
E. The governments restrict online surveys.Choose the most appropriate answer from the options given below :
If a researcher wants to select a sample from a population such that each member in the population of interest has an equal chance of being selected in the sample, the researcher is following:
Given below are two statements
Statement I: In survey research, even a large sample cannot guarantee precision.
Statement II: As large samples also do not guarantee precision, the researcher need not worry about sampling error.
In light of the above statements, choose the correct answer from the options given below
Which of the following sampling procedures will be appropriate for conducting researches with empirico-inductive paradigm?
In case the population of research is heterogeneous in nature which of the following sampling techniques will ensure optimum representativeness of sample units?
Which of the following statements fails to indicate the intent of purposive sampling?
Important Questions from Sample
When a sample is obtained by asking a participant, who is initially selected in the sample, to suggest some one else who might be willing or appropriate for study, the sample is labelled as
Identify sampling procedures in which units are chosen giving an equal and independent chance
A. Quota sampling procedure
B. Stratified sampling procedure
C. Dimensional sampling procedure
D. Random sampling procedure
E. Systematic sampling procedure
Choose the correct answer from the options given below:
Arrange in sequence the steps involved in the sampling process
A. Choose between probability and nonprobability sampling
B. Specify sampling unit
C. Validate sample
D. Determine the necessary sample size
E.Select appropriate sampling frame
Choose the correct answer from the options given below:
Which one of the following is NOT an essential characteristic of data?
Which of the following are correct about Questionnaire?
(a) In open ended question, specific responses are taken through ranking, scaled items and categorical responses.
(b) In ranking, respondent place the response in a rank order according to some criteria.
(c) In scaled item, respondent indicate the strength of their agreement only.
(d) In categorical response, respondent are given only two responses such as 'yes' or 'no'.
Choose the correct option from the codes :
