For your hypothesis you have “Experimental intervention does not affect the motivation of students. Thus, it does not increase the active participation in course content learning within the classroom environment.” But you need to develop a null hypothesis and a research hypothesis. When comparing groups, in general, the null hypothesis is that group means will NOT differ. When testing the relationship between two variables, in general, the null hypothesis is that the relationship is zero. The research hypothesis will also differ. It can be directional (group X has a higher mean score than group Y) or nondirectional (group X and group Y will differ). Your research hypothesis will affect your null hypothesis (e.g. the null hypothesis for the directional hypothesis above would be that group X has a mean equal to or less than group Y).
You said “Threats interfere with the process of data compilation thus invalidating the experiment or compromising the status of the experimental outcome. Student historical backgrounds and past performance may influence both the independent and dependent variables. This is because history both motivates and demotivates individuals. On the other hand, maturity is a factor that may render the results invalid. Students may redistribute and prioritize various activities based on time. Consequently, the critical elements are subject to a shift in priority which interferes with the experimental outcomes. Some may choose not to respond. Thus they remain just like the control group which at some point may exhibit changes concerning the environment.”
You brought up a few good points here. Here are some more potential internal threats to validity in our scenario. For example, threats to the validity could include the short time frame for the experiment. Another threat would be that with only one course there is the potential for a decline in effort, as the class ends being a contributing factor. The best way to mediate these threats would be to have the experiment run over the timeframe of a few classes to better test if a change in participation only happens when there is incentive or if there is a newly learned behavior that continues without the motivation present.