JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D IV Year BIOSTATISTICS AND RESEARCH METHODOLOGY Previous Question Paper (July/August - 2021 - R08)

Interventional studies, or clinical trials, are prospective research designs where the investigator actively intervenes by administering a specific treatment, drug, or procedure to participants to evaluate its safety and efficacy. The gold standard is the Randomized Controlled Trial (RCT).

Key components include:

• Randomization: Participants are assigned to intervention or control groups by chance to eliminate selection bias and ensure baseline comparability.
• Control Group: A comparison group receiving either a placebo, standard of care, or no intervention to isolate the effect of the treatment.
• Blinding: Masking the intervention status from participants (single-blind), investigators (double-blind), or data analysts (triple-blind) to prevent observation or performance bias.
• Study Phases: Trials are classified into Phase I (safety/dosage), Phase II (efficacy/side effects), Phase III (confirmatory large-scale comparison), and Phase IV (post-marketing surveillance).

Sample size determination is the mathematical process of calculating the minimum number of participants required to detect a clinically meaningful effect with statistical significance. An inadequate sample size leads to underpowered studies (Type II error), while an excessively large sample wastes resources and exposes unnecessary participants to risk.

The calculation depends on four primary parameters:

• Effect Size: The minimum clinically important difference (MCID) between the intervention and control groups.
• Alpha (α): The significance level, typically set at 0.05, representing the probability of a Type I error (false positive).
• Beta (β): The probability of a Type II error (false negative). The Power (1-β) is usually set at 80% or 90%.
• Standard Deviation (σ): The expected variability of the outcome measure in the population.

For a continuous outcome comparing two means, the formula is:

Where n is the sample size per group, Zα/2 and Zβ are critical values from the standard normal distribution, and Δ is the expected difference between means.