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Thursday, June 1, 2017

How do i calculate probability of a probability distribution?

How do i calculate probability of a probability distribution?

How do i calculate probability of a probability distribution?

Posted: 01 Jun 2017 02:59 AM PDT

Dear people. Hear me out.

I have histogram of the probability of certain values x of a random experiment. Its looks very nicely like a normal distribution. Then I have the data of an experiment that I did that tells how many times I measured value x. I would like to find out how likely it is to find that specific value distribution of given the probability distribution that I have but I can't figure out how to calculate this. in other words, I would like to figure out how likely it is that my measured distribution is random or ordered.

In analogy, I thow a dice 1000 times and I get the distribution of results. I want to figure out how likely it is that this distribution of numbers happened by random chance or not.

Can you help me out?

submitted by /u/TunnelFET
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By observing a radioactive atom, is there any way of knowing whether it will decay soon or in a million years' time?

Posted: 01 Jun 2017 04:35 AM PDT

Is radioactive decay truly random? And do radioactive atoms show signs that they are about to decay before they do so?

submitted by /u/xkimlam
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Is there something to addition like what addition is to multiplication?

Posted: 31 May 2017 11:27 PM PDT

So multiplication is repeated addition 2*3=2+2+2.

we know we can go further with Exponentiation being rpeated multiplication 23 = [;2\uparrow3;] = 2*2*2

and we can keep going like that [;2\uparrow\uparrow3;] = 32 = 222

[;2\uparrow\uparrow\uparrow3;] = [;2\uparrow\uparrow2\uparrow\uparrow2;] = [;2\uparrow\uparrow4;]=2222

etc.

but can we go into the other direction?

like 2+3 = [;2\downarrow2\downarrow2;]

and [;2\downarrow3;] = [;2\downarrow\downarrow2\downarrow\downarrow2;]

submitted by /u/TheWhiteWarrior
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Have we ever monitored the brain of a dying individual and if so were there any interesting phenomenon observed?

Posted: 31 May 2017 10:32 AM PDT

What's the consensus on the executive function model of ADHD?

Posted: 01 Jun 2017 07:59 AM PDT

I'm an adult who was diagnosed with ADHD as a child (called ADD at the time). Thanks to the video that was on the front page a few days ago, I was recently introduced to the work of Dr. Russell Barkley. Much of what he said about ADHD being primarily an impairment of executive function sounded like it made a lot of sense, and it matched up very well with my own experience of my disability. Is this a well established theory of the cause and nature of ADHD? Is it well supported by the work of other researchers, or is Dr. Barkley on the fringe? If it goes against the consensus, then what is the consensus? Or what are competing theories?

Here's a video that summarizes his ideas.

submitted by /u/TalksInMaths
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How pausible would it be for planes/jets to operate on solar energy?

Posted: 31 May 2017 11:14 PM PDT

How do I calculate the probability of a frequency distribution

Posted: 01 Jun 2017 03:09 AM PDT

Dear people. I did an experiment that results in a frequency for a set of stochastic variables x. I also did a computation that predicts the distribution of the variable x given random chance (the probability distribution of x given randomness). Now I would like to know how likely it is that my experiment x is just random. Similar to throwing a dice 1000 times, counting the occurence of each eye and then calculating how likely it is that this dice is fair or that it is unfair.

How does one do this?

submitted by /u/TunnelFET
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What is actually happening when I see a 'shooting star'?

Posted: 31 May 2017 06:19 PM PDT

Overheard that it is possible to represent more than 2^n states using n bits. How?

Posted: 01 Jun 2017 07:42 AM PDT

How can a spectrometer split the light into its components?

Posted: 31 May 2017 05:20 PM PDT

I understand that faraway planets' atmospheres can be analysed because light refracts differently based on what the light is passing through, but I don't know how a spectrometer can determine how many and what kinds of light(-components) make up the light we receive down here.

submitted by /u/Frieso
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Why are power outlets in the US typically in groups of 2?

Posted: 31 May 2017 01:45 PM PDT

Why do we wake up from sleeping after certain amount of time?

Posted: 31 May 2017 09:27 AM PDT

If diamonds are found in and around lava tubes, why do we not find them around Hawaii or other volcanic islands?

Posted: 31 May 2017 02:54 PM PDT

It seems to be similar in my simple mind.

submitted by /u/DC74
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Is a tube more conductive than a solid wire?

Posted: 31 May 2017 11:02 AM PDT

To be more specific, does the greater surface area of a tube allow a greater flow of electrons than a wire with an equivalent outer diameter?

If there is a difference, what is it and what are the applications?

Edit: As pointed out by /u/undercoveryankee, the phrase "equivalent outer diameter" is potentially ambiguous. The intended expression was "same diameter". Ex: a pipe with 1mm OD compared to a solid wire with 1mm OD.

submitted by /u/daerogami
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What is the origin of the anti-A & anti-B antibodies in Type O plasma?

Posted: 31 May 2017 11:27 AM PDT

A blood question that deserves a bloody answer! (Heh. Pun intended. Frustration also intended.)

I have a BS in biology and was in a discussion with my coworker. I have type O+ blood and so does he. We're wondering if people like us with Type O blood are born with the anti-A and anti-B antibodies in our plasma or if we would have to be exposed to type A/B/AB in order to get these antibodies?

Please support with reliable source if possible.

submitted by /u/ellie_love1292
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What is the law for the amount of momentum transferred in a collision of two elementary particles ?

Posted: 31 May 2017 01:58 PM PDT

Is there a law for the probability of transferring some amount of momentum between two ( lets say ) electrons, given some initial conditions ? Do they simply switch momenta or ( what i think ) is it random, depending on e.g. the angle ? What is the law ?

submitted by /u/Coousey
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How does private key encryption work?

Posted: 31 May 2017 01:39 PM PDT

I understand the basic idea that you encrypt using your private key and their public key and they can decrypt using their private key and your public key, but if your public key is the inverse of your private key, how does your private key stay secret? can't people figure it out by just finding the inverse of your public key?

submitted by /u/waltzingwizard
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Why do air bubbles "wobbles" as they rise?

Posted: 31 May 2017 09:26 PM PDT

Why dont they rise straight up?

submitted by /u/ehbuster
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If selective breeding can allow us to work towards desirable traits in organisms, would it be possible to change the likelihood of an organism's sex?

Posted: 31 May 2017 10:38 AM PDT

What happens to a phagocyte after phagocytosis?

Posted: 31 May 2017 10:55 AM PDT
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Wednesday, May 31, 2017

Where do Newtonian physics stop and Einsteins' physics start? Why are they not unified?

Where do Newtonian physics stop and Einsteins' physics start? Why are they not unified?

Where do Newtonian physics stop and Einsteins' physics start? Why are they not unified?

Posted: 30 May 2017 05:42 PM PDT

Has the introduction of emojis into Western language structures made our minds more capable of learning Eastern pictorial languages?

Posted: 30 May 2017 06:44 PM PDT

Why can't we just inject a ton of power into a phone at once to instantly charge it? Is that just too dangerous, or just not possible?

Posted: 31 May 2017 07:38 AM PDT

Why is it so hard to shoot ICBM's out of the sky?

Posted: 30 May 2017 04:21 PM PDT

We have been working on this since the 80s. It seems like an impossible feat for that era of technology; However, in the last 18 years we have only hit 10 of 18 targets in testing. It is an awful long time between tests, and the results still vary.

submitted by /u/resinis
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Does the nuclear testing make a significant contribution to the normal amounts of radiation we receive daily?

Posted: 30 May 2017 07:37 PM PDT

It has contributed in some areas such as Trinity and such, but has it made an impact on where most of civilization lives? Globally?

submitted by /u/sbundlab
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How did scientists measure the radius of atoms and other stuffs?

Posted: 31 May 2017 05:58 AM PDT

They can seem to measure very accurate things at 10 decimal places. How do they do it?

submitted by /u/AeolDrias
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How do electronics keep track of time when they are turned off/ out of battery?

Posted: 30 May 2017 06:07 PM PDT

My iPod died a few months ago and was completely without power until a few days ago when I plugged it in. When it opened it was down to the second. It also wasn't connected to wifi. How does it keep track?

submitted by /u/JBman2001
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I don't know if this is the right question for this subreddit, but how would a pack of raptors, let's say deinonychus, fair in the modern day Savannah/Serengeti?

Posted: 31 May 2017 02:18 AM PDT

Would they be able to compete with other predators like lions, hyenas, and crocodiles, or would they die out? (Assuming they can adapt to the environment) I know dinosaurs are supposed to be on average a lot larger and stronger than modern day animals, but I thought it was interesting the raptor called deinonychus only weighed 150 pounds (compared to a female lion which weights 280) was able to hunt other dinosaurs such as tenontosaurus which weighed around 2000 pounds (compared to zebras and water buffaloes which weigh around 1000 pounds). Would these dinosaurs dominate the food chain today? Or were they only specialized for the animals of their time and fail at hunting the herbivores of the savannah/Serengeti.

submitted by /u/Bosombuddies
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Why do polarised sunglasses make some screens difficult to read?

Posted: 30 May 2017 03:21 PM PDT

I'm a crane driver and find it hard to look at my instrument screens when wearing my polarised sunnies. It's difficult having to choose between reading my vitals and avoiding sun strike.

submitted by /u/Gopshop
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What does 'error variance' mean in this chart?

Posted: 31 May 2017 02:59 AM PDT

This is the chart in question. It's the results of a psychological study measuring the characteristics of mystical experiences. There are three groups of items: introvertive/extrovertive/interpretative, and I'm struggling to make sense of the numbers and what the implication is.

submitted by /u/Euthalius
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Can pions (or other mesons) form a "nucleus" by binding to other pions via the strong force?

Posted: 30 May 2017 07:19 PM PDT

For example, a π+ and π0 acting as the meson equivalent of the proton and neutron. Can this not happen because the π0 decays too quickly, or is there another reason?

Also, if these meson "nuclei" can occur, are they potentially more stable than the constituent mesons (like neutrons become stable when bound in a nucleus)?

submitted by /u/USI-9080
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Would syringe hold liquid in vacuum?

Posted: 30 May 2017 05:27 PM PDT

As the tilte reads. I think it should, because it does hold water and it does not care about the atmospheric pressure. But also, shouldn't the liquid vaporize?

What if syringe would hold liquid with much higher/lower density in medium which has much lower/higher density than the liquid inside the syringe? Would the liquid also hold?

submitted by /u/paulysch
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How are seedless watermelon grown if they are seedless?

Posted: 30 May 2017 03:42 PM PDT

If I point randomly into the sky, how likely is it that I'm pointing at a star?

Posted: 30 May 2017 03:52 PM PDT

Edit: phrased differently, If I extend a line from the tip of my finger to the edge of the observable universe, what's the probability that that line intersects with the body of a star?

This was inspired by reading about Olber's Paradox or the "dark night sky paradox".

submitted by /u/hexachoron
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What is used to date old stone tablets?

Posted: 30 May 2017 11:01 PM PDT

I was curious and tried to find the oldest known piece of writing and in seeing all the stone tablets I was wondering how their age is determined. With old papyrus or parchment they can use radiocarbon dating to find out when the paper was made to have a rough idea. I know rocks can be dated using different radioactive dating and magnetic dating techniques but that just tells you when the stone was made not when the story was written. Even if you date the layer they are in wouldn't that just tell you when that rock was created?

submitted by /u/MelodicBenzedrine
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Are there currently any known uses or benefits to inducing radioactivity in normally non-radioactive substances?

Posted: 30 May 2017 04:54 PM PDT

What are cosmic rays, and what are some ways that astronauts would be able to protect themselves if they were exposed to them?

Posted: 30 May 2017 05:32 PM PDT

Where do cosmic rays come from in large quantities? I know that some of them come from the sun, but where else?

And, hypothetically, say that a team of astronauts on a space shuttle happened to venture into an area with a lot of cosmic rays. How would they protect themselves, if they even could? If they couldn't, what would be the effect?

submitted by /u/Xilc
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What happens to the parts of the brain which control amputated body parts?

Posted: 30 May 2017 04:00 PM PDT

How would relativity affect the "length" of speed of light data transfer like a radio transmission?

Posted: 30 May 2017 04:39 PM PDT

Let's say that I was to send a 10 second long Radio Transmission from an object going 0.9 the speed of light relative to another receiver.

Would that receiver get a "sped up" and compressed radio transmission?

submitted by /u/Karnman
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If electricity can be turned into heat and photons with a light bulb, can photons be turned back into electricity?

Posted: 31 May 2017 03:50 AM PDT

How Does Auto-Shut Off Engine Design Not Destroy Engines?

Posted: 30 May 2017 09:30 AM PDT

I rent cars quite a bit for work and over the last six months I have gotten a handful that have a feature where they basically shut off when the car stops and then start back up when the car tries to move.

I've been told starting up the engine is one of the harshest things an engine goes through, yet this approach to design seems to unnecessarily add a ton of off/on cycles to a drive.

Is the notion / assumption that start up is the harshest out of date or are special precautions taken to mitigate the damage of this particular feature?

submitted by /u/dza76wutang
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Why does the current decrease when the voltage increases in the National Grid?

Posted: 31 May 2017 03:27 AM PDT

In school I learned that in circuits that voltage and current are proportional to each other; when one increases the other does aswell. In the National Grid however, the opposite seems to happen. Is it something to do with the transformers or that it's an alternating current? Thanks!

submitted by /u/Nafiblu
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Does lepton number have to be conserved in nuclear decay?

Posted: 31 May 2017 03:21 AM PDT

I was looking at examples of radioactive decay earlier, and I noticed something strange.

In an alpha emittance example, it gave Uranium-238 decaying to Thorium-234 via the emittance of an Alpha particle and a neutrino.

Why would a neutrino be produced here? As far as I'm aware, conservation rules apply to all decays don't they? There are no leptons on the Uranium side, so all it does is offset the balance.

submitted by /u/TRPAlternative
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Tuesday, May 30, 2017

Why in binding energy calculations do we include emitted neutrons but not electrons?

Why in binding energy calculations do we include emitted neutrons but not electrons?

Why in binding energy calculations do we include emitted neutrons but not electrons?

Posted: 30 May 2017 04:55 AM PDT

(not asking for help on a specific question)

In the first part of the decay a neutron is fired into a nucleus the decays and produces 2 daughter nuclei and some other emitted neutrons. We include these in the binding energy calculations.

After this the two daughter nuclei decay via beta emission. Producing emitted electrons. We don't include these in the calculations

When I say calculations mean using binding energies and mass difference.

In both cases the particles are emitted and not part of a nucleus. Is it because the neutrons have nuclear forces between the quarks inside them?

Is it because the neutrons were initially a part of the nucleus? But then what about neutrons that are fired into the nucleus?

Do they count as being a part of the nucleus too?

submitted by /u/RavernousPenguin
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Do man-made electronics cumulatively make a significant contribution to the Earth's magnetic field?

Posted: 29 May 2017 05:40 PM PDT

Could scientist determine what emotions a person is experiencing by looking at brain scans only? If so, could the same technique be used on animals?

Posted: 29 May 2017 06:39 PM PDT

What are the reasons why we can't get rid of toxic waste and non-recyclable materials by throwing them into space?

Posted: 30 May 2017 12:49 AM PDT

How do power lines work ? What happens when there is a downed power line and how is it fixed?

Posted: 29 May 2017 06:00 PM PDT

Not sure if this is the right sub reddit for this , but I'm interested in the science behind power lines and how they work

submitted by /u/PuzzledPieces
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Why is the center tap on a residential pole transformer at 0 volts?

Posted: 30 May 2017 06:53 AM PDT

Is it because there's a standing AC wave in the secondary winding with a node at the center, or is it because it's tied to the earth there? Or some other reason?

Thanks!

submitted by /u/anylchemist
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Is there a way to allow a portion of an EM field to pass through a material that would then prevent it from escaping?

Posted: 30 May 2017 02:23 AM PDT

I am doing an experiment but I was trying to out if there is a material that would allow EM field pass through only in one direction? The idea is a isolation portions of the energy so a Faraday cage would not work as the field would be more or less absorbed by the cage. Ideally I would like to find something that works like a one way mirror. Thanks!

submitted by /u/Scirroco
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Has modern medicine helped or hurt human evolution?

Posted: 29 May 2017 06:21 PM PDT

Since people tend to live longer despite illness and genetic abnormalities it seems like we are decreasing the effects of natural selection.

submitted by /u/millerml21
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What happens in our blood circulation when we go pale after "seeing a ghost"?

Posted: 30 May 2017 04:31 AM PDT

Do the Marine Isotope Stages 1 and 5.5 reflect high or low eccentricity ?

Posted: 30 May 2017 04:16 AM PDT

How do H2 molecules behave in a double-slit experiment?

Posted: 29 May 2017 05:42 PM PDT

As I poorly understand it, placing a camera in a classical double-slit experiment collapses the particles' wave functions, fixing their position to a narrow window and preventing the large-scale wave interference that would otherwise occur. The idea that a particle's position is not fixed is a tough one to fathom, and I have spent some time imagining how particles act once they are bound up in a molecular structure. Surely, baseballs thrown at a double-slit wont interfere with each other, so where can we draw the line? The smallest molecule I can think of is H2, but I cant imagine how being bound to each other would influence the wave structure of the two hydrogen atoms. Can somebody help me out?

submitted by /u/dragonite_myFriendxx
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If you hit a small bouncy ball and a normal sized baseball with a baseball bat, which will travel the most distance?

Posted: 30 May 2017 03:41 AM PDT

Why do penises originally grow in response to testosterone, but then stop growing even though testosterone is still produced?

Posted: 29 May 2017 10:29 PM PDT

How could we go about converting energy into matter?

Posted: 30 May 2017 06:43 AM PDT

We've been converting matter to energy on an industrial scale since the 1940's - but has anyone been able to / does anyone know how we would turn energy into matter?

I know this has no practical use, but it'd be interesting to know.

submitted by /u/Lorzonic
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What are the differences between taking two 20mg pills and one 40mg pill?

Posted: 29 May 2017 06:57 PM PDT

Do x-rays occur in nature?

Posted: 29 May 2017 04:57 PM PDT

How do you construct phylogenies?

Posted: 30 May 2017 03:33 AM PDT

When constructing phylogenies, how do we determine which traits were inherited from a common ancestor and which traits may have evolved independently in a different lineage? To give an example, one thing that ties early whales to artiodactyla is the shape of the astragalus. How do we know it didn't even evolve independently?

submitted by /u/Trunyon90
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Why are there so many different units of measurement that deal with radiation?

Posted: 29 May 2017 06:19 PM PDT

Rads, Rontgens, Grays, Becquerel, Sievert, Curies, etc. Why are there so many?

submitted by /u/doowi1
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Way to detect and cancel high pitch noise?

Posted: 29 May 2017 01:08 PM PDT

Lately my dog has acted the way he behaves when he hears fireworks. He shows anxiety, tries to climb on me, licks his lips. There are no human discernible noises during these episodes. It's only a theory but I am wondering if he is hearing something I can't hear. Is there an affordable , attainable device to detect noises dogs hear? How about one to cancel them out in his general environment? Granted it could be something else. He'll go to the vet. But now I'm curious about the sound detection and cancellation.

submitted by /u/dogrescuersometimes
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What happens to your vocal cords when you lose your voice?

Posted: 29 May 2017 04:14 PM PDT

How much has battlefield medicine/field surgery changed since WWII?

Posted: 29 May 2017 06:19 PM PDT

I watched a large portion of ''Saving Private Ryan'' today and Wade's death really got to me, but it also got me wondering how much battlefield medicine had changed since the second World War. So, has it changed and how much has it changed? If Wade had the same injuries in a war today, would he survive?

submitted by /u/8footmidget
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What happens in a neutron-neutrino interaction?

Posted: 29 May 2017 12:15 PM PDT

I was wondering what happens in a neutron-neutrino interaction. Is it similar to beta minus decay in the sense that the down quark changes into an up quark and a w boson and that w boson decays into an antineutrino and an electron, then the antineutrino and neutrino annihilates?

I couldn't find any answers in any of my resources and on this sub too, unless it's hidden deep within a question about beta decay.

submitted by /u/Madetoaskquestions
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