What is the most effective way to minimize the effect of all extraneous variables between the experimental group and the control group? (Select all that apply.)
a. Match the groups by hand.
b. Randomly assign subjects to group.
c. Use a large sample.
d. Place subjects into groups according to the extraneous variables they possess.
e. Allow subjects to choose the groups to which they want to belong.
ANS: B, C
Design strategies used to control extraneous variables include random sampling, random assignment to groups, selecting subjects that are homogeneous in terms of a particular extraneous variable, selecting a heterogeneous sample, blocking, stratification, matching subjects between groups in relation to a particular variable, and statistical control. Random sampling increases the probability that subjects with various levels of an extraneous variable are included and are randomly dispersed throughout the groups within the study (Thompson, 2002). This strategy is particularly important for controlling unidentified extraneous variables.
You might also like to view...
Genetic testing reveals that an African American man and woman who are engaged to be married are both carriers of the gene that causes sickle cell disease
When planning this couple's follow-up counseling, the nurse should recognize what implication of this assessment finding? A) There is a 25% chance that a child of the couple would have sickle cell disease. B) The man and woman each have an increased risk of developing sickle cell disease later in life. C) There is 50% risk of sickle cell disease for each of the couple's children. D) Their children's risk of sickle cell disease will depend on a combination of genetics and lifestyle factors.
A nurse is providing patient education for a patient who has been prescribed diphenoxylate HCl with atropine sulfate. Which of the following instructions would be important for self-administration of this drug?
A) Take the drug with a meal B) Take the drug with fruit juice C) Decrease the dosage when the number of stools decreases D) Continue therapy until the physician discontinues the drug
A nurse collects a clean-catch specimen from a client at a health care facility. Which of the following statements describes a clean-catch urine sample?
A) A sample of fresh urine collected in a clean container. B) A sample of urine collected in a sterile room environment. C) A sample of urine collected over a period of 24 hours. D) A sample of urine that is considered sterile.
A nurse is caring for a pregnant client receiving oxytocin. The client is in the third stage of labor. The nurse would expect to administer oxytocin by which route?
A) Intravenous B) Intramuscular C) Subcutaneous D) Intranasal