Which Situation Represents a Threat to Internal Validity in an Experimental

question 32

Multiple Choice

Which situation represents a threat to internal validity in an experimental study measuring the effect of a videotape of discharge instructions for patients who underwent coronary artery bypass graft (CABG) surgery?

• A) Both men and women undergoing CABG surgery were included as participants in the study.
• B) Two new surgeons began performing CABG surgery during the study period.
• C) Patients in the experimental group discussed aspects of the videotape with patients in the control group.
• D) Data collection for the videotape and control groups took 1 year.

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Definitions:

Acetone

A volatile, colorless liquid used as a solvent and an antiseptic; it's the simplest and most important of the ketones.

ΔH°

The standard enthalpy change of a reaction, indicating the overall heat absorbed or released under standard conditions.

Bond Dissociation Energies

The energy required to break a specific chemical bond in a molecule, indicating the strength of the bond.

Initiation Step

The first stage in a chemical reaction where reactants begin to form intermediates.