1 of 14

SAMPLING ERROR

SRUTHI S

2 of 14

SAMPLING

sample are taken from population

selecting observations to provide an adequate description

3 of 14

SAMPLING ERROR

differences between the sample and the population

Increasing the sample size will reduce this type of error

4 of 14

5 of 14

Types of Sampling Errors�

Sample Errors

Non Sample Errors

6 of 14

Sample Errors

Error caused by the act of taking a sample

results to be different from the results of census

Differences between the sample and the population occur

Statistical Errors are sample error

We have no control over

7 of 14

Non Sample Errors

Control by Sample Size

Non Response Error

Response Error

8 of 14

Non Response Error

  • occurs when units selected as part of the sampling procedure do not respond in whole or in part

9 of 14

Response Error

occurs during data collection, analysis or interpretation

  • Respondent error (e.g., lying, forgetting, etc.)
  • Interviewer bias
  • Recording errors
  • Poorly designed questionnaires
  • Measurement error

10 of 14

Respondent Error

  • respondent gives an incorrect answer
  • respondent misunderstands the requirements
  • lack of motivation to give an accurate answer
  • "lazy" respondent gives an "average" answer
  • question requires memory/recall

​

11 of 14

Interviewer Bias�

Different interviewers administer a survey in different ways

Differences occur in reactions of respondents to different interviewers, e.g. to interviewers of their own sex or own ethnic group

Inadequate training of interviewers

Inadequate attention to the selection of interviewers

There is too high a workload for the interviewer

12 of 14

Measurement Error

The question is unclear, ambiguous or difficult to answer

The list of possible answers suggested in the recording instrument is incomplete

Requested information assumes unfamiliar to the respondent

The definitions used by the survey are different from those used by the respondent (e.g. how many part-time employees do you have?

13 of 14

Key Points on Errors

inevitable in production of national statistics.

steps taken to minimise

question procedures adopted for data collection, and data verification

attempt to resolve queries immediately they arise.

results presented can be interpreted meaningfully.

14 of 14

Thanks…