how does a double blind experiment work

HESI LPN

LPN Nutrition Practice Test

1. How does a double-blind experiment work?

A. Both subject groups take turns receiving each treatment.
B. Neither subjects nor researchers know which subjects are in the control or experimental group.
C. Neither group of subjects knows whether they are in the control or experimental group, but the researchers do not know.
D. Both subject groups know whether they are in the control or experimental group, but the researchers do not know.

Correct answer: B

Rationale: The correct answer is B. In a double-blind experiment, neither the subjects nor the researchers know which subjects are in the control or experimental group. This helps to eliminate bias and ensure that the results are more objective. Choice A is incorrect as in a double-blind experiment, subjects do not take turns receiving each treatment; it is about masking the treatment allocation. Choice C is incorrect because it implies that the researchers are aware of the group allocation, which goes against the principle of blinding in a double-blind study. Choice D is incorrect as both subject groups should not know whether they are in the control or experimental group to maintain the blindness of the study.

2. What is a primary goal of managing diabetes mellitus in children?

A. Promote weight maintenance
B. Prevent episodes of hypoglycemia
C. Ensure normal growth and development
D. Optimize blood sugar control

Correct answer: C

Rationale: The primary goal of managing diabetes mellitus in children is to ensure normal growth and development. This involves maintaining stable blood glucose levels to prevent complications. Option A is incorrect because promoting weight gain is not a primary goal in managing diabetes; rather, the aim is to maintain a healthy weight. Option B is not the primary goal; although it is important to prevent episodes of hypoglycemia, the main focus is on overall management. Option D is incorrect as optimizing blood sugar control is a means to achieve the primary goal, which is ensuring normal growth and development.

3. What is a causative factor of Hirschsprung disease?

A. Frequent evacuation of solids, liquids, and gases
B. Excessive peristaltic movement
C. Absence of parasympathetic ganglion cells in a portion of the colon
D. One portion of the bowel telescoping into another

Correct answer: C

Rationale: The correct answer is C: Absence of parasympathetic ganglion cells in a portion of the colon. Hirschsprung disease is a congenital condition characterized by the absence of nerve cells (ganglia) in parts of the colon. This absence leads to a lack of peristalsis in the affected segment, resulting in severe constipation and bowel obstruction. Choices A, B, and D are incorrect. Choice A describes symptoms of diarrhea rather than a causative factor of Hirschsprung disease. Excessive peristaltic movement (choice B) is not a causative factor but rather the opposite, as Hirschsprung disease is associated with reduced peristalsis. Choice D, which refers to intussusception, is a different condition unrelated to Hirschsprung disease.

4. The parents of a child with sickle cell anemia ask why their child experiences pain. What is the most likely cause?

A. Inflammation of the vessels
B. Obstructed blood flow
C. Overhydration
D. Stress-related headaches

Correct answer: B

Rationale: In sickle cell anemia, pain is primarily caused by the obstruction of blood flow by sickle-shaped cells. This obstruction leads to inadequate oxygen supply to tissues, resulting in tissue damage and pain. Choice A, inflammation of the vessels, is incorrect as it is not the primary cause of pain in sickle cell anemia. Choice C, overhydration, is unrelated to the pathophysiology of sickle cell anemia and would not lead to the characteristic pain experienced. Choice D, stress-related headaches, is also unrelated to the underlying mechanisms of pain in sickle cell anemia.

5. What should the nurse anticipate as challenging in caring for a child with acute glomerulonephritis?

A. Forced fluids
B. Increased feedings
C. Bed rest
D. Frequent position changes

Correct answer: C

Rationale: The correct answer is C: Bed rest. Implementing bed rest can be challenging, especially in active children, but it's necessary to manage the symptoms of acute glomerulonephritis. Forced fluids (choice A) may be required to maintain hydration but are not typically challenging. Increased feedings (choice B) and frequent position changes (choice D) are not primary interventions in the care of a child with acute glomerulonephritis.