> The most appropriate null hypothesis in this lovely study is “does theanine REDUCE anxiety”, not “does theanine change anxiety either up or down”. Neither of

> The most appropriate null hypothesis in this lovely study is “does theanine REDUCE anxiety”, not “does theanine change anxiety either up or down”. Neither of those is a hypothesis, which require a prediction not just a question. The null hypothesis for this experiment would be "Theanine has no effect on stress".