3 "Internal validity in research" refers to :

Mrs. h, age 42 years, is experiencing severe rheumatoid arthritis in her wrists, fingers, and knees. the joints are quite inflamed, red, and swollen. she is sitting rigidly in a chair and refuses to put on a sweater, even though she is shivering, or let anyone touch her arms. she has been prescribed an analgesic and an anti-inflammatory drug, but her dose is not due for another hour. she is feeling nauseated, so she has not eaten for the past 8 hours. based on patient history and the signs and symptoms, discuss how the effects of pain are exacerbating her condition.