An investigator while investigating the life expectancy of i.v drug abusers divides a sample of patients into HIV- positive and HIV-negative groups. What type of data does this division constitute?

Likert Scale: –  Is also known as ‘Summative scale’ –  Is a ‘type of Ordinal scale’ –  Is generally used to quantify attitudes and behaviour –  ‘Responses are graded on a continuum’ (For example: Strongly agree – Agree – Neutral – Disagree-   Strongly disagree). Guttman Scale: –  Is also known as ‘Cumulative scale’ –  Contains a ‘series of statements that expresses increasing intensity’ of a characteristic and respondent is asked to agree or disagree to with each statement. Note: In the given question, an investigator, investigating the life expectancy of IV drug abusers divides a sample of patients into HIV- positive and HIV- negative groups; Since there is no order of characteristic and it cannot be measured directly, it can’t be an ordinal data or metric data respectively. Thus it is nominal data (based only on names, i.e. HIV- positive and HIV- negative groups).