Aresearcher would like to study the effects of smoking on respiratory functioning.
there are two groups:
1. participants who smoke one pack a day
2. participants who smoke two.
this is a study

Prospective study

Explanation:

A prospective study measures the outcome AFTER the exposure, in this case the smoking habbit is the exposure and the outcome that is looked for is the development of a disease.

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This two groups are referred to as Cohort and the study is a Cohort study

Explanation:

A cohort is a group of people sharing the same experience and having common features. Examples of Cohort group can include

A cohort study is a comparative observational study in which cohorts are grouped by their exposure status and followed up for a period of time to determine if one or more will come down with the disease or outcome.

Using this research above, two groups have been selected ( participants that smoke one Pack a day and participants who smoke two pack) and this groups will be followed up for given time to see whether they come down with respiratory disease.

There are two types of Cohort studies namely: