Thatcher thinks that anxiety can impair test performance, so he does relaxation exercises before his exam. He is extremely relaxed during the exam and does poorly. Thatcher did not take into account the complete relationship between physiological activation and performance, as described by

The Yerkes-Dodson law

Explanation:

Have you noticed that we sometimes perform better when we're nervous? For example, one might perform better at an event when one is excited. This relationship between an individual's arousal levels and his or her performance is called the Yerkes-Dodson Law.

The Yerkes-Dodson Law posits that a relationship exist between arousal and performance and an increase in arousal can boost performance, but the performance boost is only up to a certain point. In case of an excessive arousal, the performance reduces.

world war i had a devastating effect on german-americans and their cultural heritage. up until that point   german-americans, as a group, had been spared much of the discrimination, abuse, rejection, collective mistrust experienced by so many different racial and ethnic groups in the history of the united states. indeed, over the years, they had been viewed as a well integrated and esteemed part of american society. all of this change with the outbreak of war.