I would approach this like a coach. The way I see this is your Tuesday average is probably closer to your true average than any of the other days. Here is why, and this is all speculation for the sake of internet fodder:
My assumptions:
1. Work Monday through Friday, 9-5 type job.
2. Have a desire to improve.
3. After previous topic replies, dmonroe814 may not be as much a spring chicken as others or as he/she used to be.
Analysis:
1. Tuesday you are somewhat well rested and work has yet to really bear down on you for the week. You have energy and so does your body including legs. You bowl with an attentive mind and rested body and bowl well.
2. Friday's are the end of the week and can be extremely taxing on the mind. The time spent at the bowling center is more a getaway from work than it is fun with friends with friendly competition. Body may be a little less rested from a week of a shorter sleep schedule and the legs show it. Scores suffer accordingly.
3. Saturday starts and you finally get some rest. Depending on the time you bowl, you may have had a busy day of "honey-dos". Or a fun day watching a sports team do well or bad. Body feels better than the day before and your scores show this. Mind is probably feeling better also.
4. Sunday is the end of the weekend and by now you have completed a list of 237 honey-dos and mowed the lawn and washed the car. (maybe not) But much like some people need a vacation from vacation, you too need some extra rest from a busy weekend. Body is feeling it also and thus scores show it also.
5. Back to Tuesday with at least one night (Monday) to rest the body. Already know you bowl well on Tuesday's so your mind is in a better place and so is your body. Good bowling is achieved.
I know a lot of this is intended as speculation, but there is a message here. There are a lot of factors that go into the way a person bowls/performs. It can range from mental, physical, emotional or whatever. Volatile personalities will usually perform inconsistently. They can have amazing nights and horrific nights. This is why most professional athletes try to maintain as even a keel as possible. Don't get too excited when the good happens and don't get too down when the bad happens. This way, your performance is more true to your preparation and talent.
Try to approach your bowling in a more process oriented manner. Execute the single shot in front of you and that is all. Be confident in your decision on any particular shot and take the result as information only. Don't let a pocket 7-10 tell you how bad a bowler you are or how crappy the carry is. Let it tell you what you need to do to improve the outcome of the next shot. And once you step up for the next shot, the past shots are only information, not an indication of what you will do.
PS. I don't mean this analysis to be true for dmonroe. I just used it as a basis of my conclusion.