Jenae's study ignored the fact that only some of her coffee choices had caffeine, even though her co$-$workers preferred caffeinated coffee. Therefore, Jenae decided to label one type of decaffeinated coffee as having caffeine to see what would happen.

As she anticipated, this coffee became more popular with her co$-$workers, and they claimed that the extra boost of caffeine helped them focus on their work.

The growing popularity of the decaffeinated coffee among co$-$workers, under the false impression that it gave them extra caffeine, is an example of $\_\_\_\_\_\_\_\_.$