Asample that is treated exactly like the other experimental groups except that the variable is not applied to it is a(n) (1 point) observation variable control hypothesis,

A sample that is treated exactly like the other experimental groups except that the variable is not applied to it is a control hypothesis. A control group is used in the statistics to measure the effects of a test. It is a set of individuals who have not been involved in the manipulation of one or more variables consisting of the test (this is the "control condition"). It is compared to the experimental group which has been manipulated to determine their effects and serves as a reference control value.

Well, l think that some effective communication is, emotional barriers and lack of attention, interest distraction or irrelevance. also some physical disabilities such as hearing problems or speech difficulties.      l hope i am correct  and you good luck.

Making sure the equipment is cleaned daily and insuring proper hygiene is kept up with the working staff.