Your hypotheses and research scenario is generally well structured but there a

 
Your hypotheses and research scenario is generally well structured but there are a few suggestions for clarification and improvement. First, with the grouping variable being different groups (mindfulness training vs. no meditation) this would be an independent sample (betweens subject) t-test. 
Here are some suggested revisions: 
Null Hypothesis (H0):
   – There is no recognizable distinction between the control and mindfulness training bunch regarding mean detailed stress levels.
   – Suggested Revision: There is no statistically significant difference between the mean perceived stress levels of the control and mindfulness training groups.
2. Alternative Hypothesis (H1):
   – The mean perceived stress levels of the mindfulness training and control groups contrast altogether.
   – Suggested Revision: There is a statistically significant difference in the mean perceived stress levels between the mindfulness training and control groups.
You also mentioned a within-Subjects design: In the case of a within-subjects design, the mean perceived stress levels of participants in each group will be compared using the paired sample t-test before and after the intervention.
Nice job overall. Any questions let me know!