3.2b(iii) Controls

Question 1

Negative control

Answer 1

The negative control provides results in the absence of a treatment.

Question 2

Positive control

Answer 2

A positive control is a treatment that is included to check that the system can detect a positive result when it occurs.

Question 3

Controls

Answer 3

Control results are used for comparison with the results of treatment groups.

Question 4

Placebos

Answer 4

Placebos can be included as a treatment without the presence of the independent variable being investigated.
Placebo effect is a measurable change in the dependent variable as a result of a patients expectations, rather than changes in the independent.