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Cap'n Refsmmat

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Posts posted by Cap'n Refsmmat

  1. I did some poking around but I don't have any ideas why that would happen. WordPress is running its scheduled tasks occasionally like it should.

     

    I just set up a cronjob to force them to run hourly. You might try scheduling another post and seeing if it appears on time.

  2. What makes you think that a balloon will be lighter? I assume you want to fill it with pressurized gas? Such gas cylinders are really heavy. If you want to slow down the fall of anyone from an airplane, I would recommend a parachute.

    Airbags usually use chemical gas generators instead of pressurized tanks, since you don't want to keep a pressurized air tank in your car all the time.

     

    But yes, I feel like a > 200mph impact into the ground probably destroys the structure of the aircraft so much that the airbag can't be much help.

     

    Ejection seats would be great, but you wouldn't be able to use a laptop safely (it'd be blasted off your lap and into the guy behind you upon ejection) or move around much, and you'd have to be strapped in much more securely. And have an oxygen mask on at all times. And so on.

  3. This is just a pure thought. I am not very sure about this pure thought. My question is can more ships and boats and submarines cause the sea level to rise?

    Yes, but not by very much. xkcd's What If? has covered the opposite of this question:

     

    How much would the sea level fall if every ship were removed all at once from the Earth's waters?

     

    About six microns—slightly more than the diameter of a strand of spider silk.

    http://what-if.xkcd.com/33/

     

    So all of the ships in the world contribute very little to the rise in sea level. Read the full article for all the fun details.

  4. Perhaps those readers have nothing to compare your style to other than the non-indented single-spacing that online editors force on us. I don't so much object to a double-space between paragraphs containing multiple lines as I object to double-spaced single lines as in Externet's post in this thread.

    Admittedly our software makes the block layout uglier than it has to be. Instead of letting me choose the spacing between paragraphs to be narrower, it merely inserts a blank line between each, so I can't control the gap. If I could I would make it more subtle.
  5. -----Part of precision in writing is formatting and I particularly dislike how indenting is so difficult on a computer. Oh for the ease of the typewriter in this regard! (To indent these paragraphs I inserted white dashes.)

    Why insist on indenting, though? A blank space between paragraphs serves the same purpose. It wastes vertical space, but that is not in short supply on the Internet.

     

    On the topic of precision: I agree wholly with Ophiolite. Writing exists to convey meaning, and in science the meaning is often complex and counterintuitive. Only with precision and careful planning will your writing succeed.

     

    Recently I have been writing a book about the improper use of statistics, and many points center on a subtle misunderstanding of some tricky statistical concept. My editor frequently writes comments like "I didn't quite understand this paragraph," and when I read it again I realize I've said something entirely misleading. ("Power of the coin? What does that even mean?") Readers are endlessly imaginative misinterpreters of statistics, and I have to choose every word with incredible care to convey my meaning correctly.

     

    The tragedy is that few of my readers will read as carefully as my editor does, and so most will miss important points.

  6. An interesting but conspiratorial point: even if you do believe that climate change is real, but do not think it is the government's role or duty to address it (or think the remedies are worse than the problem), pretending to be a moron is an incredibly effective obstruction tactic.

     

    So if someone believes that action on climate change would kill the American economy by excess regulation, then it's best for them to pretend climate change is a liberal myth.

  7. I'm fine with you writing about your book on your blog, since it's a blog. On the forums, you can bring it up when it's relevant to discussion ("I explain this in more detail in my book"), but creating threads to advertise would clearly be over the line.

     

    It's a rather fuzzy boundary and I'm not sure where to draw the line. Just how much do you have to bring it up before it's advertising? I'm not sure. Perhaps some other moderators can weigh in.

     

    From a practical standpoint -- don't worry, we won't just ban you the instant we see a link. If a moderator does object, they may remove the link and send you a message.

     

    (I'm interested in what the mods think for my own reasons too. I'm also writing a book and will find it hard to resist bringing it up. I don't want to abuse my admin position to advertise it freely.)

  8. In addition to the great points above about learning and interacting with people and experiencing/exposing myself to viewpoints different from my own, I have found that sites like these also provide me with a relatively safe place to improve the style and the way I express my thoughts and to become a more articulate human being overall.

     

    More than once, I've been in meetings at work or giving a presentation to a large audience and thought, "I'm much more comfortable and capable of sharing this idea because I've had so much practice writing thoughts like these online. A few years ago, I really would have struggled to communicate that so clearly."

    Yes! I would not be writing a book now if I had not spent my teenage years trying to imitate Sayonara's incredibly clear debate style.

  9. If you change your display name, that will change the name that appears on all of your posts. It will not, however, change the name you use to log in.

     

    "Current password" is the password you currently use to log in; you're required to enter it when setting a new password as a security measure.

     

    I do not know what "Local password" is; I don't see it in my account, since I'm an administrator and see different controls.

  10. I'm attempting to read Darrell Huff's unpublished manuscript How to Lie with Smoking Statistics, commissioned by the tobacco industry in the 60s to respond to the claim that smoking causes cancer. (Huff more famously wrote How to Lie with Statistics, probably the most popular statistics book ever written.)

     

    I managed to dig up most of the unpublished chapters but I'm trying to figure out why it wasn't published; as far as I can tell, he was ready to sign a contract and then nothing happened.

  11. You need to accelerate protons to incredible energies, which requires running them around in a loop while you pump more energy into them. But to pull them into a loop you need to keep bending their paths, which takes energy. So you don't want to force them to make sharp bends.

     

    There's just no way of accelerating a proton to such a high speed in a short distance. You couldn't make an electromagnetic field strong enough to do it in a few inches.

     

    One current field of research is laser wakefield acceleration, where lasers are used to induce an incredibly strong electric field to accelerate electrons much faster than you could normally achieve:

     

    https://en.wikipedia.org/wiki/Laser-wakefield_acceleration

  12. I'm still waiting for an answer to my earlier question.

    To whom does that seem impractical?

    Because people do it a lot.

    Indeed. A great deal of theoretical statistics is about quantifying the errors of different methods and determining which ones perform the best under different circumstances.

     

    There's been a lot of work on robustness, for instance, where estimators are checked to see how well they behave when their assumptions are not met.

  13. No.

    The use of "squared" is not an arbitrary choice, it follows from the properties of the distribution.

    Do you actually know that maths behind statistics, or are you criticising it blindly?

    I'm not sure what your argument is here. I can write the normal distribution in terms of the precision (1/variance), the standard deviation, or any other weird quantity I'd like; the original normal distribution was differently parametrized than the one we have now. So while the sample variance is a good way of estimating the variance parameter, we could equally well calculate the sample precision or sample standard deviation.

     

    But I also don't understand AdvRoboticsE529's point.

  14. I have no opinion on the approximation theory, the purpose for the replacement of statistics should be to eliminate uncertainty, hence estimations will not be preferred regardless of their relations.

     

    You use too much metaphors, and is very unspecific, difficult to discuss with you, I try. You also shouldn't be so presumptuous in that many problems cannot be solved with "explicit" equations, this is the mentality in which should be discouraged, and is encouraged by statistics, just because certain problems seems difficult currently does not mean it is unsolvable, and should be worked on towards certainty in contrast to living in uncertainty. I previously asked my teacher how could you determine the steepest gradient of any given function, she said it is not possible (I searched online for a method, which is beyond my current skill yet is possible), other questions I have asked includes the summation of root numbers which is premature yet does not mean it is not possible to be precise in the formulation of formulas, you are not unlike many authorities who are confident that what they know is the truth, relativity shows that time is relative, a contrast to the previous authorities who refused such concepts.

    The nature of science is that statistical arguments are gradually replaced with exact mathematical ones -- when they can be. Kepler's orbital laws, for example, were basically an empirical and statistical argument from data, with no theoretical grounding. Once Isaac Newton formulated a theory of gravity, he was able to replace the empirical argument with a theoretical one and show why Kepler's laws had to be true.

     

    Statistics is a way of making progress in science even without the exact theory. Without statistics to give us a rough picture, we will not know what our final theory should look like

     

    On the other hand, my current research (I am getting a PhD in statistics) isn't something that can be replaced with exact formulas. I'm trying to map the background radiation levels over a wide area. Background radiation levels are a function of the radioisotopes buried in the ground and in common building materials, such as concrete. There's no a priori way to figure out where the radioisotopes are, unless you can devise math to predict exactly how the Earth would be shaped from four billion years ago to today, including construction and man-made activity. So I have to measure empirically, and to do that I need statistics.

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