What are the pros and cons of the sampling methodology used?

My Daily data Time spent in gym 55 60 60 60 57 50 54 55 45 18 150 46 40 45 45 40 40 40 34 30 30 30 30 30 30 Mon Tues Wed Thurs Fri Sat Sun Week 1 Week 2 Week 3 Week 4 Made with Livegap Charts