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 common sign of hypothyroidism in children?

A. Weight loss
B. Increased heart rate
C. Dry skin and constipation
D. Elevated blood pressure

Correct answer: C

Rationale: Dry skin and constipation are typical signs of hypothyroidism in children. Hypothyroidism results from an underactive thyroid gland, leading to symptoms such as dry skin and constipation. Weight loss (Choice A) is more commonly associated with hyperthyroidism, where the thyroid gland is overactive. Increased heart rate (Choice B) and elevated blood pressure (Choice D) are also more characteristic of hyperthyroidism rather than hypothyroidism. Therefore, the correct answer is dry skin and constipation (Choice C) when identifying signs of hypothyroidism in children.

3. What is the first-line treatment for a child with a bacterial ear infection?

A. Intravenous antibiotics
B. Oral antibiotics
C. Nasal decongestants
D. Antihistamines

Correct answer: B

Rationale: The correct answer is B: Oral antibiotics. Oral antibiotics are the first-line treatment for bacterial ear infections in children as they effectively target the infection at the source and help alleviate symptoms. Intravenous antibiotics (Choice A) are typically reserved for severe cases where oral antibiotics are not sufficient. Nasal decongestants (Choice C) and antihistamines (Choice D) are not the primary treatments for bacterial ear infections. Nasal decongestants are used for nasal congestion, and antihistamines are used for allergies. However, these medications do not directly address the bacterial infection in the ear, unlike oral antibiotics.

4. What is the main purpose of Recommended Dietary Allowances (RDAs)?

A. To provide guidelines for nutrient intakes that meet the needs of most healthy people.
B. To specify the minimum amount of nutrients required for survival.
C. To establish maximum safe levels of nutrient intakes.
D. To recommend specific nutrient intake levels to prevent chronic diseases.

Correct answer: A

Rationale: The main purpose of Recommended Dietary Allowances (RDAs) is to provide guidelines for nutrient intakes that meet the needs of most healthy people. Choice B is incorrect because RDAs aim beyond just survival requirements. Choice C is incorrect because establishing maximum safe levels is the role of Tolerable Upper Intake Levels (ULs). Choice D is incorrect because preventing chronic diseases is more associated with Dietary Reference Intakes (DRIs) like Adequate Intakes (AIs) and Tolerable Upper Intake Levels (ULs). Therefore, the correct answer is A.

5. A child develops a strong dislike of noodle soup after consuming a bowl while sick with the flu. Her reaction is an example of a food-related ___.

A. habit
B. social interaction
C. emotional turmoil
D. negative association

Correct answer: D

Rationale: The correct answer is 'negative association.' A negative association occurs when a person develops a dislike for a food due to a past negative experience, such as getting sick after eating it. In this case, the child's dislike of noodle soup is specifically linked to the negative experience of consuming it while sick with the flu. Choices A, B, and C are incorrect because the situation described does not relate to habit formation, social interactions, or emotional turmoil, but rather to a learned aversion based on a specific negative event.