Final answer:
The nurse researcher likely used the Theory of Planned Behavior (TPB) to study adults' intentions to donate blood and their actual donation behavior.
Step-by-step explanation:
The nurse researcher likely used the Theory of Planned Behavior (TPB) to study adults' intentions to donate blood and their actual donation behavior. The TPB proposes that intention is the most important determinant of behavior and is influenced by three factors: attitudes, subjective norms, and perceived behavioral control.
Attitudes refer to an individual's positive or negative evaluations of donating blood. Subjective norms represent social pressures to donate blood, including the beliefs and expectations of others. Perceived behavioral control refers to the individual's perception of their ability to perform the behavior of donating blood.
By examining these factors, the nurse researcher could gain insights into the factors that influence adults' intentions to donate blood and their actual behavior.