Exercise is the main cause of heart disease.

Heart disease is unrelated to diet.

Sugar might be causing heart disease.

Sugar is beneficial for heart health.

To focus on individuals with high sugar intake.

To avoid bias and get a representative sample of the population.

To only include individuals from urban areas.

To ensure only healthy individuals are surveyed.

Observational study

Case study

Sample study

Experimental study

They require a large number of participants.

They cannot establish causality between variables.

They are only applicable to small populations.

They are too expensive to conduct.

Heart disease risk

Age of participants

Exercise frequency

Sugar consumption