Domain: purplemath.com
Stories and comments across the archive that link to purplemath.com.
Comments · 35
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Re:FAKE NEWS. female engineers are rejects
I was going with a proper definition, being that this site is aimed at non-idiots I figured that proper use of technical terms would be assumed.
See here for definition:
http://www.purplemath.com/modu...This:
Mean, median, and mode are three kinds of "averages". There are many "averages" in statistics, but these are, I think, the three most common, and are certainly the three you are most likely to encounter in your pre-statistics courses, if the topic comes up at all.The "mean" is the "average" you're used to, where you add up all the numbers and then divide by the number of numbers. The "median" is the "middle" value in the list of numbers. To find the median, your numbers have to be listed in numerical order from smallest to largest, so you may have to rewrite your list before you can find the median. The "mode" is the value that occurs most often. If no number in the list is repeated, then there is no mode for the list.
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Re:Like what?
Depending on whether you're considering the mean, median, or mode, the "average" may or may not be at the 50% point. Seemingly pedantic, but useful - having one billionaire could drive up the mean income in an entire county full of poverty to the point where it looks like you don't need to focus safety-net programs there. Meanwhile, I'll link you to a site on these averages, since they explain it better than I can. Now, it's entirely possible that the mode - the most common value - could be well above or below the 50% point - the median, really - in a skewed distribution.
You have to know which average to look at; some will tell you damn dirty lies about certain datasets. -
Re:ATTN: Potential New Hires
I think you are confusing mean with median.
I think you are confusing the phrase "about half", especially in the context of what Google's N would be. P.S. The audience is not math/stat students.
There could well be a few very well paid people that skew the mean...
Except that the data being referred to is pay by position. Exceptionally talented people would have very different positions than what most applicants are applying for.
Then I think you would want to go with the mode average for a given position...
http://www.purplemath.com/modules/meanmode.htm -
Re:Pi
Ooh, that's an oldie. Let me leave this here for you.
AC because I don't have karma to burn. Also I won't upvote own anonymous comment (I wouldn't be anonymous, then, would I?). -
Pi = 3 Myth DebunkedRead 'em and weep:
Linky . .TL;DR
Basically, there's an inner measurement and an outer measurement, and we're not given the thickness, Or it was understood at the time. Something like that. -
Re:where is the controversy?
I believe if one reads that particular passage you'll find that the measurement hit ~3.1395.
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Re:Rest of World
Despite that being a hoax, biblical pi is about the same as pi itself once you realize the wall of the bowl had thickness to it
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Re:What The Fuck?
You're confusing 'average' and 'median.'
Not only is the median a type of average, but for a normal distribution -- a Gaussian "bell curve" -- all three types of average -- median, mean, and mode -- are the same value.
From your own article above:
"The "mean" is the "average" you're used to, where you add up all the numbers and then divide by the number of numbers."
Used without qualification, the word average tends to imply this usage."The "median" is the "middle" value in the list of numbers."
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Re:What The Fuck?
You're confusing 'average' and 'median.'
Not only is the median a type of average, but for a normal distribution -- a Gaussian "bell curve" -- all three types of average -- median, mean, and mode -- are the same value.
Now you know.
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Re:X11 RDP
Is there a reason that you aren't using a more standard exponential notation, ie. $10^8?
You mean a standard exponential notation... like Engineering notation?
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Re:when these genius people are 100%
For 100% certainty you need religion
Or math, the queen of all sciences (ducks from flames)
Math is not a science, it's based on axioms like religions are based on dogmas.
the math majors get no heat despite being arrogant WRT possession of the truth in general and their insistence that the value of PI is an unbiblical irrational number instead of gods written truth of exactly three.
That's because math majors usually don't believe to metropolitan myths to bolster their self confidence. They don't need to.
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Re:There's Your Problem Right There
"And he made a molten sea, ten cubits from the one rim to the other it was round all about, and...a line of thirty cubits did compass it round about....And it was an hand breadth thick...." — First Kings, chapter 7, verses 23 and 26
Clearly Pi = 3
The part about a "hand breadth thick" may be significant. If one assumes that the "one rim to the other" refers to the outer diameter and the 30 cubits refers to the inner circumference, you get a value of pi much closer to the expected value. See this article for more details.
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Re:Santa of course is not an effin elf.
I will start with my conclusion, since if you have time for only one more response or to read one more comment, I would prefer it be this, and would be happy to leave it here:
This whole discussion started off with you stating that people who believe in religion suspend logic, and are in fact illogical. We have gone back and forth for several posts, and I feel you have been courteous enough. At the end, though, I wonder: do you feel that I have shown an inability to reason? Would you say I have been illogical?
And now on to the wall of text.
Just as Rainbows were considered signs from the heavens, but now we understand them as a product of refraction
Non sequitur-- there is no law I am aware of that says each thing can only be one thing at a time. A rainbow could have existed before the flood, and then post-flood been declared a sign of a new covenant; it can simultaneously be the result of water droplets acting as a prism and refracting light into its constituent parts. Likewise, God could have created the universe, and have used methods that are observable to use today (a burst of energy and matter from a single point).
The scientific method is always applicable.
Thats just plain not true. Quick: Apply the scientific method to Nihilism, or post-modernism. Guess what, you cant, since it only works with testable hypothesis. You are trying to shoehorn a scientific device for testing into all areas of life, when it is not designed to play that role. You can be rational without trying to find a testable, quantifiable, measurable hypothesis in every single thing.
It makes up the part where there is a God.
Begging the question. It would simplify things and make for much shorter posts if we left out the parts where assumptions are made which at the get go rely on my being wrong. Its circular, its not helpful, and it just generates more argument.
does you beleiving that I have an apple make it more likely I have a magical wand?
It is a good deal easier if instead of "likely" we use the word "confidence", as statistics and mathematics have nothing to do with whether something is or is not true. We can talk of our level of confidence that it is, and I would say that in your example your truthfulness in one area adds some small degree of confidence to your other claims; but not enough for me to believe them. If on the other hand, having known you for 50 years (as say a brother) I had never known you to be anything other than perfectly honest, and perfectly sane, it would carry a much greater degree of weight. If another friend who had likewise been perfectly honest had witnessed it from afar, and I knew you two had not collaborated, it would shift the balance to me cautiously wanting to see the thing for myself.
The bible generates a great deal of confidence for me in the way that it self-verifies: parts of the OT and NT agreeing in subtle and not easily noticed ways; predictive prophesy prior to events that end up being remarkably true; measurements and descriptions that are startlingly accurate (such as a vessel's measurement that indicates a working knowledge of pi as 135/43, or 3.1395); dates and names that are accurate; minor details that do not read as a work of fiction or legend, especially given the time period and literary styles; etc.
To state that it loses your confidence because "it declares a God, and clearly God does not exist, thus the Bible is not reliable and therefore there is no God" is not fair at all.
Because Julius Caesar didn't do impossible things.
Once again, begging the question: whether something is impossible or not in this case depends on whether the Bible is true or not.
All of them. Tricks, coincidences, phonomena we have later explained.
Im not aware of an exp
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Re: The way things are supposed to be.
PS: I was going to find something witty about the bible calling pi = 3, but then I learned something new today
:)
http://www.purplemath.com/modules/bibleval.htm (cool stuff for math history geeks!)In the book 'A history of pi', the author looks at this passage. I forget the details, but this argument of outer vs. inner circumference has been used before, but the justification is invalid: a few passages later, there is a clarification that shows that they meant the outer radius.
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Re: The way things are supposed to be.
My Christian Comrades,
The Lord tells us that wives should submit to their husbands, and He granted men their greater ability to do math and science to help enforce this view. All of the neo-Nazi bra-burning feminists who wish to bridge this so-called "gap" are merely trying to undermine the Christian values of our nation. This is the way things are supposed to be, so there is no "gap."
Sincerely, Jake
My Fellow Mathematicians,
The Calculus tells us that The Numbers should submit to their domains, and It granted mathematicians their greater ability to do math and science to help enforce this view. All of the neo-Nazi math-burning Luddites who wish to bridge this so-called "gap" are merely trying to undermine the Mathematical values of our scientific establishment. This is the way things are supposed to be, so there is no "gap.", other than the gaps between prime numbers.
Sincerely, The Troll Feeder
PS: I was going to find something witty about the bible calling pi = 3, but then I learned something new today :) http://www.purplemath.com/modules/bibleval.htm (cool stuff for math history geeks!) -
Re:*/ same precedence. L to R or R to L is ambiguo
I was always taught that multiplication and division were of equal precedence since they are equivalent operations algebraically
Completely accurate. The full mnemonic, for the record, is "Please Excuse My Dear Aunt Sally", or "Parentheses Exponents Multiplication Division Addition Subtraction".
That being said, a number of people take the mnemonic a little too literally, believing it to mean that multiplication comes before division and addition before subtraction. In reality, both have the same priority, as they are equivalent operations, as you stated.
Quickest link I can find to explain it: http://www.purplemath.com/modules/orderops.htm
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Re:Goes both ways...
After all, if you really have heard the claim 30 times over, surely it should be easy to refute?
I have, and they are-- I could likely dig up several Amazon.com posts from a year ago where I refuted several of your points. But the thing is, when youre willing to make flat out false statements in challenge to my position (such as your assertion that the bible punishes rape victims for not screaming, when that verse does not use or imply "rape" in ANY English translation I could find-- but rather heavily implies consent), there can be literally-- and I mean literally-- no end to the objections. Whether or not they have merit seems, in the end, to be of little importance. And this has been my experience. I no sooner finish my 3 hour long explanation of one thing, having answered each question about each piddling point, when some other objection is raised("Bible claims pi is 3!" is a favorite of mine), which I must spend more time refuting... only after countless hours and explanations to find out that there was NEVER honest inquiry or debate in mind, but merely a driving desire to ridicule, shame, and stand on a soapbox as much as possible.
So forgive me if I am less than willing to answer such assertions when they dont even come from YOU, but from another site. I understand that, at times, others may state a point better than you do; this is why I mentioned CS Lewis' Mere Christianity. But if you want to rely on others to make your arguments, then why could I not do the same and point to the volumes upon volumes of apologetic work by Spraul, Van Til, Keller, and the rest? They certainly have expertise that surpasses mine. No, the issue is not whether there are athiests who happen to be more clever than I am, or whether there are apologists who are more clever than you, but whether or not yours and my positions hold water. And to cite a youtube video that 30 seconds in gets basic points of fact (ie, what the bible actually states) wrong is unimpressive, and really damages your credibility, as does turning to the Onion in ANY kind of serious conversation.
I would be more than happy to go into detail on one of the above points, but I just feel more and more we are going in circles in 30 different topics simultaneously. Want to discuss the incarnation, and how it saves? Love to. Want to discuss why rejection of God merits death? Great. Set the parameters, I dont want to give the impression I am evading, but to argue so many topics simultaneously while giving none the depth they require for a proper answer is not helpful to anyone, and presumably the purpose of such a discussion is to better understand the other's position, and to seek out the weaknesses in our own; or else to pursue truth. So choose an area of discussion, ask your question, and I will be happy to go into all the depth you need (or that I can give). -
Re:TeX
No, the Bible says that if one builds a bowl w/ a certain outside diameter and a certain wall thickness, the inside circumference will be such that pi is ~3.14:
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links mentioned in replies
online videos: algebra + calculus
http://justmathtutoring.com/
http://www.mathtutor.ac.uk/
http://www.khanacademy.org/
http://www.graderocket.tv/index.php
Uni Maths Videos
http://ocw.mit.edu/OcwWeb/Mathematics/
http://press.princeton.edu/video/banner/
http://academicearth.org/subjects/mathematics
http://freescienceonline.blogspot.com/2009/01/calculus-video-lectures-bonus-basic.html
http://www.apple.com/education/itunes-u/ (requires iTunes download)
Resources from Universities
http://www.germanna.edu/tutor/helpful_handouts.asp?menuchoice=Helpful%20Handouts (wow)
http://mathforum.org/
Free online books:
http://www.jamesbrennan.org/algebra/systems/solution_set.htm
http://cnx.org/content/m18205/latest/?collection=col10624
http://www.jirka.org/diffyqs/ (Differential eqns)
http://www.purplemath.com/
http://tutorial.math.lamar.edu/
PowerPoints
http://www.online.math.uh.edu/HoustonACT/
Tutoring services
http://www.nutshellmath.com/
Collections of Links
http://math.about.com/od/mathhelpandtutorials/Math_Help_and_Tutorials_by_Subject_and_or_Topic.htm
http://pathstoknowledge.net/
Problems
http://projecteuler.net/
Some computer Resources
http://www.graphmatica.com/
http://archives.math.utk.edu/visual.calculus/ -
Bad textbooks, bad teachers.I don't know about other people, but it seems like the biggest inherent flaw is not a lack of resources for math, but rather that people generally don't know where to go.
Up until right now, I just used http://www.purplemath.com/, and had no idea that other resources existed so extensively.
I enjoy math, but I'm also an unmedicated ADHD child - lectures frequently just bounce off of me; and attempting to learn from a course assigned textbook is a joke... these are designed around a lecture format that doesn't work perfectly for everybody. Nothing is more frustrating than hitting a wall due to not fully processing a lecture, and having the textbook be worthless ($180 worth of worthless, too.)
I think the best suggestion is just to wander your way through some of the recommended books and sites and not force it; as others have mentioned, if you're actively enjoying the learning experience, it'll just flow naturally. Or, it'll fail miserably... either way, progress (not necessarily forward) will be made!
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Some sites I've come across
Helpful handouts from Germanna Community College's tutoring Center. (I used to work there a few years ago; these resources are not only helpful, but free.)
Drexel's Math Forum (full disclosure: I'm a current Drexel employee and student -- but the Math Forum strikes me as pretty cool.)
Project Euler(more oriented toward programming and numerical methods, but interesting site for developing your math skills. The problems range from not-too-hard to mind-boggling.)
Purple Math -
Mean and median are both "averages"
"Most people believe "the arithmetic mean" and "the average" to be synonyms, though there are many sorts of averages."
Indeed, in fact Mean and median are two different kinds of "averages". By convention "The average" in statistics refers to the arithmetic mean. Median is by definition the value that divides the population in half. -
Re:But according to...
The site I linked to showed why. Unless you find something about that logic unbelievable which I find hard to believe seeing how the math actually works out. What is boils down to is that you have a word problem with incomplete knowledge and are attempting to work a problem from it without deriving the rest of the knowledge.
This has nothing to do with being a holey roller or anything of the sorts. It has nothing to do with the accuracy of the bible (which you seem to be confused a little about) either. The measurments talk about the outside of the rim and the inside of the rim and when you take the thickness of the rim/wall into consideration, Pi works out to about 3.14. Claiming it is 3 is not using your critical thinking skills, it's repeating a known falsehood.
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Re:But according to...
Oh how little do you know. If you would have read the verse and applied literal physics to the situation you would understand that the wall comprising of rim to rim cannot be paper thin. In fact, when you add the thickness of the rim into the equation, Pi comes out to an except-able number.
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Re:This just in
Actually, that isn't as scary as you think. The biblical reference your making can logically be concluded to 3.14 and not 3 exactly.
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OK, now I'm feeling guilty
OK, now I feel bad for you. Look, you're confusing the concepts of mean and range.
Consider the set {10,10,10,10,10,10,10}
The mean (average) is 10. That doesn't mean half the set members are less than ten. It simply means that the range (largest member minus smallest member) is small, or in this case zero.
Here's a great middle school tutorial on mean, median, mode and range: http://www.purplemath.com/modules/meanmode.htm
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Re:As a literary....
You seem to be confused about quite a few things. First is Pi IT actually comes out to around 3.14 which is close enough.
Second, You have to understand the mindset of the churches who perpetrated the acts you mention. They actually misread revelations and though Jesus was coming back after 1000 years. When that didn't happen, they thought they were supposed to create the promised kingdom on earth. That responsibility has since changed hands a few times and then the concept of the rapture comes around with a more literal reading of revelations. But it was in all cases, the error of man which caused the ills you speak. And it was the misconception of biblical prophecy compounded by canons that caused it, not the word of god.
Now, the canonization preserved those words. But it isn't what they did to preserve the words but what they did to understand them that created the problems. You really have to look at it as a two stage process. First, preserve the words and meaning. Second, to discover messages and act on them. The second part is the part that went bad because they were the sole works of man. That is a little but of an over simplification but it isn't far off from the concepts.
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Re:Blashphemy !
This assumes that the bowl was infinitesimally thin. In the real world, "it was an hand breadth thick" (1 Kings 26). Taking this into consideration you get an approximation for pi of 3.14.
I'll see your random link and raise you one. -
Re:0.08 percent?
Apparently the chances of being taught good fundamental math is lower than the chance of meeting IRL a freak
I wouldn't be so sure. There are plenty of sites that can help with basic math, if you just look for them. I guess you belong to the "overblown" club, huh? -
Re:Make it readable
I was interested in learning more about (like Calculus) on Wikipedia and found that I couldn't even understand the description of the subject!
Calculus Intro: http://www.math.umn.edu/~garrett/calculus/first_ye ar/notes.pdf
Calculus Intro: http://www.ms.uky.edu/~ma123/ma123.pdf
Trig: http://www.sci.uidaho.edu/POLYA/math144/video_inst ruction/video_instruction.htm
Algebra: http://www.learner.org/resources/series66.html
Algebra: http://www.purplemath.com/modules/index.htm
Graphing Calculator: http://www.pacifict.com/
Extras:
http://hss.energy.gov/NuclearSafety/techstds/stand ard/hdbk1014/h1014v1.pdf
http://hss.energy.gov/nuclearsafety/techstds/stand ard/hdbk1014/h1014v2.pdf
"Mathematics: From the Birth of Numbers" by Jan Gullberg. -
Re:Long division
Synthetic Division... less writing and faster compared to polynomial long division:
http://www.purplemath.com/modules/synthdiv.htm
If the students make it that far they should be able to pick up 'long division' much faster then teaching it now. Umm and when your dividing by a mononomial it's really just a matter is canceling and reducing. -
Re:I swear this is not my homework
Looks like somebody needs to lern2quadraticformula, noob.
http://www.purplemath.com/modules/quadform.htm -
Re:Shyeah
Maybe its just me, but perhaps the Bush administration should focus on the US's literacy and mathematical skills compared to the rest of the globe, as opposed to our position in the world's broadband distribution.
Personally, I think the two are tightly related. There are a lot of reasons that Americans are relatively poorly educated, and the Internet's no magic bullet. But there's a lot you can do with the Internet to improve education. Unlike TV, which ended up a wasteland, there are already many good free educational resources. And anything that helps parents monitor their local schools strikes me as helpful in improving the system. -
Re:Some hoaxes based on realityhe he
The hoaxers fell for an urban legend. The Bible doesn't say that pi is 3.0.Does the Bible say pi equals 3.0?
Does the Bible Give a Wrong Value for Pi?
I see four major issues in the relevant Scripture:
- We don't know the exact length of a cubit.
- We aren't sure of the complete geometry of what was being measured.
- The Scripture is giving measurements of real-world objects, not presenting a mathematical theorem. If the numbers seem wrong to us, we're not understanding what was being measured.
- We don't know what kind of rounding, if any, was being used.
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Re:Ugh, ICRYou clearly aren't singing the same tune as ICR -- I got that, and I should said it more clearly. I wonder if they'd even consider you a creationist. To me, ICR's brand of creationism is the important one to address because it's the one that's impeding the teaching of evolution in the US.
I'd be curious to see an informed attempt to
fit a literal interpretation of Genesis to current scientific understanding. My conclusion is that it just doesn't fit, even if you stretch or retranslate "day" by a factor of a trillion. How can you deal with having plants arrive before the sun? So I'd mostly be curious about how the inconsistencies are explained away.
Biblical literalism isn't really all that interesting to me, except from an anthropological perspective. There are people for whom it's an honest and consistent belief system, but I have no common ground with them. They start with faith in the bible's literal truth and end doing dances like this to reconcile their belief with logic. I start by trusting observation and reason, look at the bible as a historical document, and see the same passage as a minor case of sloppy journalism. It doesn't make for a satisfying debate.