A molding machine in a factory was not working very well. About a third of the time, the plastic squirt guns that it was making come out with a flaw in the handle. The repair mechanic adjusted the stamping pressure. Then she ran one gun through. It came out just fine, so she figured she had solved the problem. What was/were the error(s) in the conclusion of the repair mechanic? a. Not enough subjects
b. Subjects were not similar
c. Conditions were not kept the same
d. The experiment was not reproduced

a. Not enough subjects

Explanation:

In the context, it is given that in a factory, a molding machine is not working properly. The molding machine produces a gun made of plastic. But the machine was produces a defective piece about a third of he time it produces the gun.

The mechanic adjusted and repaired the stamping pressure and ran only one gun through which came out to be fine. But there was an error in the conclusion of the repair mechanic as she did run the machine only one time. She did not have enough subjects and should have run many times to see if the error still exists, as the machine showed error only about a third of the time during the process.

Thus the error in the experiment includes the lack of the enough of the subjects. We cannot come to the conclusion only with one time success.