At the end of the analysis, you must either reject the null hypothesis, or retain the null hypothesis based on the data

At the end of the analysis, you must either reject the null hypothesis, or retain the null hypothesis based on the data. The particular context/scenario translates that decision to a Yes or No.  

Here are two scenarios:

e.g. "Yes, this website is more popular than the other website", vs. "There is no significant difference in popularity between the websites" (null hypothesis).

e.g. "No, males do not spend more than females", vs. "There is no significant difference in spending between males and females" (null hypothesis).

etc. 

In these scenarios, what would be a Type I, alpha-level error? And what would be a Type II beta-level error? 

If there is a Type I or a Type II error present, how would you know?