Research Methodology & Design Flashcards

What is the null hypothesis in a study testing whether a drug changes expression of a target gene?

Answer: There is no difference in expression between treated and control groups

The null hypothesis states no effect; the study tests evidence against it.

Which RNA quality metric should be reported to support the reliability of RT-qPCR results?

Answer: RNA integrity number (RIN) or equivalent

RIN or similar integrity scores show that degraded RNA is not biasing expression results.

An acceptable linear dynamic range for a qPCR standard curve is typically confirmed by what criterion?

Answer: R² ≥ 0.98 across the dilution series

A high correlation coefficient across serial dilutions shows linear response over the range.

In a case-control study using PCR to detect a viral marker, what is a major concern in selecting controls?

Answer: Controls should come from the same source population as cases

Controls drawn from a different population introduce selection bias.

Spiking an exogenous control template into each sample before extraction primarily helps detect what?

Answer: Extraction failure or PCR inhibition

A delayed or absent spike-in signal indicates loss during extraction or inhibition.

Which outcome describes a Type I error in a PCR expression study?

Answer: Concluding a gene is differentially expressed when it is not

A Type I error is a false positive, rejecting a true null hypothesis.

Why should exclusion criteria for samples (e.g., Cq > 35 or failed controls) be defined before data analysis?

Answer: To prevent post hoc data selection bias

Pre-specified criteria avoid selectively excluding data to achieve desired results.