Cross-sectional study

Case-control study

Cohort study

Randomized controlled trial

To investigate the relationship between an exposure and an outcome over time

To compare the characteristics of two or more groups of people

To estimate the prevalence of a disease in a population

To evaluate the effectiveness of a new treatment

In a case-control study, the exposure is measured before the outcome, while in a cohort study, the exposure is measured after the outcome.

In a case-control study, the participants are selected based on their disease status, while in a cohort study, the participants are selected based on their exposure status.

In a case-control study, the data is collected retrospectively, while in a cohort study, the data is collected prospectively.

In a case-control study, the participants are followed over time, while in a cohort study, the participants are not followed over time.

Simple random sampling

Systematic sampling

Stratified sampling

Cluster sampling

To ensure that the sample is representative of the population in terms of certain characteristics

To reduce the sampling error

To increase the precision of the estimates

To facilitate data analysis

Convenience sampling

Purposive sampling

Snowball sampling

Quota sampling

To collect data in a standardized and systematic manner

To ensure that the data is accurate and reliable

To facilitate data analysis

All of the above

Questionnaire

Interview schedule

Observation checklist

Laboratory test

Informed consent

Confidentiality

Privacy

All of the above

To test the feasibility of a research study

To estimate the sample size needed for the main study

To develop and refine data collection tools

All of the above

A variable can take on different values, while a constant cannot.

A variable is measured, while a constant is not.

A variable is used to describe a population, while a constant is used to describe an individual.

None of the above

A qualitative variable is measured on a nominal or ordinal scale, while a quantitative variable is measured on an interval or ratio scale.

A qualitative variable is measured in words, while a quantitative variable is measured in numbers.

A qualitative variable is used to describe a population, while a quantitative variable is used to describe an individual.

None of the above

A dependent variable is the outcome of a study, while an independent variable is the exposure.

A dependent variable is measured on a nominal or ordinal scale, while an independent variable is measured on an interval or ratio scale.

A dependent variable is used to describe a population, while an independent variable is used to describe an individual.

None of the above

A hypothesis is a specific prediction about the relationship between two or more variables, while a theory is a general explanation of a phenomenon.

A hypothesis is tested through research, while a theory is not.

A hypothesis is used to describe a population, while a theory is used to describe an individual.

None of the above

A correlation is a relationship between two or more variables, while a causation is a relationship where one variable causes the other.

A correlation is measured on a nominal or ordinal scale, while a causation is measured on an interval or ratio scale.

A correlation is used to describe a population, while a causation is used to describe an individual.

None of the above