Which experiment would most likely contain experimental bias?
a. a student tests the attraction of bees to flowers by placing four different flowers in the same location and counting how many bees visit each.
b. a company that makes pain relief medication tests the effectiveness of their own medicine compared to that of three other brands.
c. a chemistry class performs an experiment in which each reaction has the same amount of starting material and begins at the same temperature.
d. a lab performs a test by giving bacterial colonies the same amount of different antibiotics and growing them under the same conditions.

B. A company that makes pain relief medication tests the effectiveness of their own medicine compared to that of three other brands.

Explanation:

In experimental bias the researcher is more likely to attempt to manipulate or produce results that show their work in a positive outcome. In this case, the company is aiming to perform research on their product that goes against their competitors.

This bias is often unconscious and can be introduced at any stage of the experiment process; it is likely to affect experimental design, data analysis and interpretation of the results obtained. The company is likely to choose or 'cherry pick' data  that best supports their claims while misrepresenting the effectiveness of their competitors products.

Typically, double blind studies are performed in order to mitigate this particular bias.