Dr. Bryson is a health psychologist who researches nutrition. She is curious as to whether a new drink additive will help people consume fewer calories during a meal. The drink additive is a white, odorless, tasteless powder that a person can add to any drink. She collects a random sample of 63 overweight students on campus and measures the calories they eat during lunch using a bomb calorimeter. She then gives this additive to the same 63 participants to use at dinner and measures how many calories they eat (again using the bomb calorimeter). Which of the following threats to internal validity will Dr. Bloedorn NOT be worried about? a. Placebo effects
b. Attrition
c. Testing effect
d. Demand characteristics

Option A

Explanation:

In simple words, The placebo effect occurs when ailments resolve notwithstanding the use of a pseudo medication. Psychological variables such as expectancy or traditional training are thought to have a role. The placebo effect has been shown in studies to help with pain, weariness, and depression.

Thus, from the above we can conclude that the correct option is A.

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a is your answer!

the correct answer is the following is a list of inventions made in the medieval islamic world, especially during the "islamic golden age" (8th to 13th centuries),[1][2] as well as the late medieval period, especially in the emirate of granada and the ottoman empire.

science and technology in the islamic world adopted and preserved knowledge and technologies from contemporary and earlier civilizations, including persia, india, china, and greece-roman antiquity, while making a number of improvements and innovations.