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 one characteristic that differentiates vitamins from minerals?

A. Vitamins are organic compounds.
B. Vitamins provide energy.
C. Vitamins are considered micronutrients.
D. Vitamins are essential in small amounts.

Correct answer: A

Rationale: The correct answer is A. Vitamins are organic compounds, containing carbon, which is a key characteristic that differentiates them from minerals. Choice B is incorrect because vitamins do not provide energy; they are not a source of calories. Choice C is incorrect as both vitamins and minerals are considered micronutrients due to being essential in small amounts. Choice D is incorrect because while it is true that vitamins are needed in small amounts, this is not the characteristic that sets them apart from minerals.

3. What is a common symptom of a respiratory infection in infants?

A. Wheezing
B. High appetite
C. Increased thirst
D. Lethargy

Correct answer: A

Rationale: Wheezing is a common symptom of respiratory infections in infants, often associated with coughing and difficulty breathing. It occurs due to the narrowing of the airways. Choice B, 'High appetite,' is incorrect as respiratory infections usually lead to a decrease in appetite rather than an increase. Choice C, 'Increased thirst,' is incorrect as it is not a typical symptom of a respiratory infection in infants. Choice D, 'Lethargy,' can be a symptom of respiratory infections but is not as specific and common as wheezing.

4. What is the appropriate intervention for a child with an undescended testicle?

A. Wait until puberty
B. Perform an orchidopexy
C. Administer hormone therapy
D. Increase physical activity

Correct answer: B

Rationale: The appropriate intervention for a child with an undescended testicle is to perform an orchidopexy. This surgical procedure is recommended if the testicle has not descended naturally within the first year of life. Waiting until puberty is not advised as early intervention is crucial for optimal outcomes. Administering hormone therapy is not the first-line treatment for an undescended testicle and is typically not recommended. Increasing physical activity does not address the underlying issue of an undescended testicle and is not a suitable intervention.

5. 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.