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 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.

3. What is the primary treatment for a child with an anaphylactic reaction?

A. Oral antihistamines
B. Intravenous fluids
C. Epinephrine injection
D. Antipyretics

Correct answer: C

Rationale: The correct answer is C: Epinephrine injection. An epinephrine injection is the primary treatment for an anaphylactic reaction in children. Epinephrine acts quickly to reverse severe symptoms such as difficulty breathing, low blood pressure, and hives. Oral antihistamines, although useful for milder allergic reactions, are not sufficient to manage the potentially life-threatening symptoms of anaphylaxis. Intravenous fluids may be necessary to support blood pressure in a child with anaphylaxis but are not the primary treatment. Antipyretics, on the other hand, are medications used to reduce fever and are not indicated as the primary treatment for an anaphylactic reaction.

4. How much energy is required to raise the temperature of one kilogram of water by 1°C?

A. 10 calories
B. 100 calories
C. 1 kilocalorie
D. 10 kilocalories

Correct answer: C

Rationale: The correct answer is 1 kilocalorie. This is the amount of energy required to raise the temperature of 1 kilogram of water by 1°C. Choice A (10 calories) and Choice D (10 kilocalories) are incorrect as they do not represent the correct unit of measurement for this specific scenario. Choice B (100 calories) is also incorrect as it overestimates the amount of energy required. The specific heat capacity of water is approximately 1 calorie/gram °C, which means that 1 kilogram (1000 grams) of water requires 1 kilocalorie (1000 calories) to raise its temperature by 1°C.

5. Which nutrient is classified as a micronutrient?

A. minerals
B. proteins
C. alcohols
D. carbohydrates

Correct answer: A

Rationale: The correct answer is minerals. Micronutrients are required by the body in smaller amounts compared to macronutrients like proteins and carbohydrates. Proteins are macronutrients necessary for growth and repair, not classified as micronutrients. Alcohols and carbohydrates are not classified as micronutrients either.