Not the original commenter, but the math is (making some implicit, but arguably reasonable assumptions):
Probability that someone in the population has schizophrenia = (1870/500000) = 0.00374
Probability that someone does NOT have schizophrenia = (1 - 0.00374)
Then if we assume that blind people have the same rate of schizophrenia as the population,
Probability that 66 blind people ALL don't have schizophrenia = (1 - 0.00374)^66 = 0.78
There's a formalism in math/information theory describing this idea called the Kelly criterion. Not a common/colloquial phrase, but it describes a similar idea of portioning bet size according to percentage of available cash based on the risk of the bet.
Well said. In addition to that, I think a speaker's intended meaning is also important to consider.
imo, people often take what people say literally or default to a first-instinct interpretation, rather than trying to understand what the speaker is attempting to convey. I try to interpret what people say charitably (a few of my friends think much too charitably), but I really believe that the vast majority of people seldom intent any malice in their comments.
In the example, it might have been intended in an empathetic way - "Damn, sorry, I didn't realize you were still hurting. I would have extended a shoulder to you if I realized". Or a pragmatic way - "I think the situation isn't as bad as you think, want to talk about it?" It could have been bluntly honest (personally, I typically appreciate honesty over politeness) or a totally aloof statement made on reflex. It could also just have been someone being a jerk, but I suppose the point of my rambling is that there's a myriad of ways to interpret a comment, and it's largely based on both the speaker's experiences and how they communicate.
I used to keep a diary (that I stopped keeping due to lack of time) and it echoes your experience to a large extent. I mostly wrote about how I was feeling or what I did that day or what I was planning to do in the near future.
I also vastly underestimated the amount of time and energy it would take to excel in certain things (for example, I wanted to compose and play music, excel at math and physics, write fiction books, play tennis, all at professional levels) and overestimated the difficulty of a few others (namely escaping poverty/becoming wealthy). Though, I suppose this may be the consequence of work being such a major timesink in one's life and my having the fortune of various opportunities in my life.
Similarly, my desired storylines and opinions have all been roughly the same since then. There have been occasions where they shifted, but then returned as if to equilibrium after a brief amount of time. As someone who views themself as having a terrible memory, I suspect it may have less to do with memory and more to do with some stable characteristic with emergent qualities. To extend the equilibrium analogy - a spring doesn't need to "remember" its equilibrium position to reach it - after experiencing friction for enough time, it'll reach it again.
It's nice being able to see a reflection of my past self though. I think I'll try to keep a diary again.
I had a similar experience when I was doing physics in undergraduate as well. I read online and was often told that a physics degree opened a lot of doors - academia, government/industry research, engineering, high school teacher, software development. But during my senior year when applying for jobs, I was hard-pressed finding any place that was interested in me. I was fortunate enough to find a job as a laser engineer immediately after graduating, but the specific role was leading to a deadend career.
I self-studied from my alma mater's computer science program (fortunately, many of the resources were all online) and was able to pivot into a career in software development, but it was a colossal amount of work and energy. I may as well have just done the computer science degree originally. A lot of my peers who had studied physics/math also took the same route, transitioning into data science or software development.
I was curious what the margin of error for this was (I'm conjecturing the sum of widths of the fingers touching the stick), so I tried this out, but with a pencil instead of a stick.
I was consistently getting just off-center, so I was thinking maybe the 'surprise' wasn't consistent, until I realized the end of the pencil (metal + eraser) is probably denser than the wood and shifts the center of mass to exactly where my fingers ended up. :)
I remember a friend of mine settings up an IRC bot (named Zeta) like that for his sheet music forum many years ago. She was involved in a lot of hilarity - probably my favorite antics were when she randomly decided to courtmatial someone. Good times indeed! :)
Probability that someone in the population has schizophrenia = (1870/500000) = 0.00374
Probability that someone does NOT have schizophrenia = (1 - 0.00374)
Then if we assume that blind people have the same rate of schizophrenia as the population, Probability that 66 blind people ALL don't have schizophrenia = (1 - 0.00374)^66 = 0.78