Basics of study design: Practical considerations

Schematic of pre-experimental research designs.

Schematic of a quasi-experimental research design.

The randomized controlled study design.

Simple graphs that you should be able to make using a spreadsheet program that contains your experimental data.

COPD = chronic obstructive pulmonary disease; PaCOs = partial pressure of carbon dioxide, artery; PS = pressure support; RDS = respiratory distress syndrome; SIMV = synchronized intermittent mandatory ventilation

Example flowchart for selecting the appropriate statistical test.

ANOVA = analysis of variance

Types of errors in statistical decision making.

Probabilities associated with type I and type II errors.