Statistical Term- Bias


Bias is a statistical term which means a systematic deviation from the true value. It is a sampling procedure that may show some serious problems for the researcher as it cannot be reduced by mere increase in sample size. Bias is the difference between the expected value and real value of the parameter. Different types of biases are listed below-

  • Selection Bias
  • Spectrum Bias
  • Cognitive Bias
  • Data-Snooping Bias
  • Omitted-Variable Bias
  • Exclusion Bias
  • Analytical Bias
  • Reporting Bias
  • Funding Bias

Bias is mainly categorized into two different types

  1. Measurement Bias

Measurement bias takes place for the duration of the carrying out the survey and it consequences chiefly because of three reasons –

(i) Error happens while recording the data

While recording data, errors happen due to the malfunction of instruments that are used for data collection or because of ineffective handling of these tools by the researchers concerned with data collection.

(ii) Leading Questions

The questions prepared for the survey might be put in a manner to lead the responses that are preferred by the researcher. There can be more choices for the preferred retort given than for the conflicting views.

(iii) Inadvertent false responses given by respondents

There can be a situation when many responders may have misunderstood the question and chooses a incorrect option. If the sample groups composed of numerous of old people and if they asked to give answers by remembering their previous experiences, they might be providing some false inputs because of deficiency of memory.

  1.  Non-representative sampling Bias

Non-representative sampling bias also referred as selection bias. This inaccuracy occurs because of implementing random methods during the selection process. This results in an excess representation of some of the elements in the population. All the samples collected using convenience sampling are caused by the bias. These type of situation are called as under coverage bias.

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Practise This Question

Between two given rational numbers, we can find