Dr.Anderson is a nutritionist who helps clients lose weight prior to surgery.She is working with W.J. ,a male client who is planning on undergoing a heart transplant.He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast,600 for lunch,and 800 for dinner).She is curious as to whether a food journal will help W.J.reduce the number of calories he eats.A food journal is used to record everything a person eats.Dr.Anderson decides to phase in the food journal gradually,initially only recording what is eaten at breakfast during the first three days after baseline (days 4-6).During days 7-9,the journal is used at lunch,too,and during days 10-12,it also is used during dinner.Each day,Dr.Anderson's client sends her entries from the food journal and the number of calories he ate at each meal (as calculated by his wife,whose help she enlisted).The data for Dr.Anderson's study are below.

-Dr.Natchez,a colleague of Dr.Anderson,questions whether W.J.simply wrote down less in his journal as the study went on because he grew tired of completing this "measure." Dr.Natchez believes he has uncovered which of the following threats to internal validity?

Question

Dr.Anderson is a nutritionist who helps clients lose weight prior to surgery.She is working with W.J. ,a male client who is planning on undergoing a heart transplant.He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast,600 for lunch,and 800 for dinner) .She is curious as to whether a food journal will help W.J.reduce the number of calories he eats.A food journal is used to record everything a person eats.Dr.Anderson decides to phase in the food journal gradually,initially only recording what is eaten at breakfast during the first three days after baseline (days 4-6) .During days 7-9,the journal is used at lunch,too,and during days 10-12,it also is used during dinner.Each day,Dr.Anderson's client sends her entries from the food journal and the number of calories he ate at each meal (as calculated by his wife,whose help she enlisted) .The data for Dr.Anderson's study are below.

-Dr.Natchez,a colleague of Dr.Anderson,questions whether W.J.simply wrote down less in his journal as the study went on because he grew tired of completing this "measure." Dr.Natchez believes he has uncovered which of the following threats to internal validity?

Quizplus · Accepted Answer

The phenomenon of W.J. writing less in his food journal as the study progressed is an example of the testing threat, which occurs when repeated measurements alter the participant's behavior. In this case, knowing that he is being monitored and possibly trying to comply with the study requirements, W.J. may have altered his eating habits over time, leading to a decrease in the amount of food recorded in the journal. The other options are not applicable in this situation. Instrumentation threat refers to changes in the measurement tool or observer, experimental demand refers to participants altering their behavior due to the study requirements or expectations, and observer bias refers to the observer's preconceived notions influencing their observations.

DrAnderson Is a Nutritionist Who Helps Clients Lose Weight Prior