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Can you have two controls in an experiment?
Using two controls exposes the experimenter to a high risk of confirmation bias. If the experimenter resists the bias and only uses the second control as a validation tool, the experiment suffers from higher rate of false negatives than if the controls were pooled.
How do you determine positive and negative controls?
A negative control is a control group in an experiment that uses a treatment that isn’t expected to produce results. A positive control is a control group in an experiment that uses a treatment that is known to produce results.
Why is it necessary to have positive and negative controls in this experiment?
It is necessary to have positive and negative controls in an experiment to ensure that the results are due to the independent variable.
What’s the difference between a positive and negative control group?
What is the difference between a positive and a negative control group? A negative control group is a control group that is not exposed to the experimental treatment or to any other treatment that is expected to have an effect.
How to tell if a positive control is working?
It produces a prominent bacterial growth inhibition zone around the positive control disk as shown in figure 01. If you observed a prominent growth inhibition zone around the disk in the positive control, it says that the experimental setup is working well without errors.
Can a negative control be used on a growth plate?
As a negative control, you might just wipe a sterile swab on the growth plate. You would not expect to see any bacterial growth on this plate, and if you do, it is an indication that your swabs, plates, or incubator are contaminated with bacteria that could interfere with the results of the experiment.
Why do you need a negative control in an experiment?
Negative control increases the reliability of the experiment. Controls are essential elements of an experiment. They are maintained in scientific experiments to eliminate experimental errors and biases. Results of the control experiments are useful for a validated statistical analysis of the experiment.