Events Definition and 352 Threads

For a long time now I've been thinking about something I find odd about probabilities. For example, let's say that I win the lottery, something that is extremely unlikely. What is the probability that I will be struck by lightning? The odds of someone winning the lottery and getting struck by...

Hello. I have two probability density functions for two events. I would like to find the probability that they both will occur at the same time. It is simply multiplying the results of the two integrals over the time, correct? Thank you

Suppose I have two atoms that independently emit alpha particles. I want to find the mean \Delta T for the events. I then want to extend this for 3, 4 etc. atoms however what I'd like to do for more than 3 atoms is find the smallest delta T for any two emissions. What should I look at to...

Hi, I've been trying to understand the (lack of) simultaneity between events in reference frames moving wrt each other. I'd be grateful if someone could confirm that I've got things right: If two events are simultaneous in one reference frame (S'), then they will not be simultaneous in a...

After it was announced that Dale Earnhardt Sr. died in a wreck in the Daytona 500 in 2001, everyone who mentioned it acted as though it was a horrible tragedy. When boxer Beethoven Scotland collapsed during a boxing match and later died during the boxing program I was watching on tv in 2001...

Homework Statement Two events occur at the same time in inertial frame S and are separated by a distance of 1km along the x-axis. What is the time difference between these two events as measured in frame S' moving with constant velocity along x and in which their spatial separation is measured...

Hello, I have a question about coincidence event. Let us take the decay of deuteron to proton and alpha particle, (d, pα). p and α goes in opposite direction. So, if we put two detectors in opposite directions, one of them will detect p and another will detect α simultaneously (within a small...

If two events separated in space by Δx occur simultaneously according to an observer S, then the time difference for S' moving at velocity u relative to S is \Delta t' = \frac{-u\Delta x}{c^2\sqrt{1-\frac{u^2}{c^2}}} Why is Δt' negative? \Delta t' = t'_2 - t'_1, where t'_2 corresponds to...

If we have two disjoint events then it comes to reason that P(A or B) = P(A) + P(B) - 0 However, if I rewrite it as 1 - P(A' and B') how is the numerical result going to be the same? (without re-writing it back as 1 - P ((A or B)')). I assume it is 1 - P(A'|B')P(B') But how is P(A'|B')...

The course this question comes from is Modern Physics Homework Statement What is the proper time interval between two events if in some inertial reference frame the events are separated by 109m and 5s? Homework Equations I looked through my notes and under a the sub topic "Invariant...

Provided I know that after 10 attempts I will get 8 successes with a probability of a success per try being 'p', does that affect the success of the first try? My first instinct was to say it's independent because each attempt is independent but now I know this is a special case where "I know...

If A and B are two independent events then P(A intersection B) = P(A).P(B) I don't refute this but it confuses me. What is the sample space in this? For eg: - If A is the event that we get Head while tossing a coin and B is the event that we get 2 while throwing a die, then what will we be the...

(a) the shaded hopefully shows $(A\cup B)'$ (b) (i) if $(A\cup B)'= 21$ and $n(U)=36$ then $n(A\cup B)=15$ but $n(A)+n(B)=17$ so $n(A\cap B) = 2$ (ii) $P(A\cap B)$ not sure but guessing $2:17$ (c) not sure what "mutually exclusive" means but presume it has to do with the overlap...

I'm casually working on determining the probability of a team in a given sport (let's say football) reaching at least a certain level in a season. There are two main parts to this: How many games they won in the season, and how far they got in the playoffs. I'd like to assign one final number...

Hi everyone, Suppose I have two samples that can be described by an observable. Call it x. x can take on any value from 0 to infinity. The distribution of values of x for sample 1 can be described by the normalized probability distribution f(x). The distribution of values of x for...

This is a very important question for me which has bothered me greatly. I started talking about it in the Smolin cosmic natural selection thread. What I would like to know is, if the Universe started over a very large number of times (n) from t=0, the start of the big bang, In how many of these...

I'm reading "Relativity: The Special and the General Theory" and I'm at the end of Chapter 9 & confused. If I understand correctly, this is what he has said so far (in my own words): Say that lightning strikes 2 points (A and B) on a railway embankment. To determine whether the two...

Hello Everybody. Could two past events result in the same happening? For example: We have observed the "incident A" and we have two different stories to explain that incident: The "history 1" and the "history 2". Both stories are equally plausible and equally likely. The question is "which of...

Probability of "exactly one" when events are dependent The question is this: "An urn is filled with 8 green balls, 2 red balls, and 6 orange balls. Three balls are selected without replacement." What is the probability that exactly one ball is orange? I know I could just use the binomial...

RE-POST If you live in Calgary please play close attention to this. Today there was major flooding both here in Calgary and the Philippines. This is a video you need to Watch if you live in Calgary Alberta Canada And there is a Earthquake watch right now for both areas today in the world.These...

I am having difficulties understanding some lines in the book. "An event can be later than another spacelike separated event in one inertial frame and earlier in another." So for example let's take the thought experiment where lighting strikes two sides of the train, and observers in...

I understand that too long of a time scale won't resolve an event clearly, and too much has the risk of exciting whatever you're trying to measure. Is there some sort of resonant effect when you match, say, a radiation frequency to the time of an event taking place? Specifically I'm applying...

Hello I have not taken a subject in set theory, only in statistics. Maybe you guys can help me, I want to describe one of the events with the other, and I am wondering if one can do it. Lets say that we have 6 machines, of these 0, 1,2,3,4,5 or 6 of them can be in use. That is, we distingiuish...

I have a question about the concept of an 'event' in relativity theory. Can an 'event' occur simultaneously at two spatial locations, A & B where (A=x1,y1,z1, B=x2,y2,z2), AT THE SAME MOMENT IN TIME ? For example, suppose two observers at locations A and B not far separated. Can they...

Hi need help for order of magnitude estimates the question is give the numerical values for order of magnitude estimates for following . explain and justify assumptions (a) the number of cars that pass through an intersection of to busy streets during the evenning commune on a typical workday...

The question... Two events are observed in a frame of reference S to occur at the same space point, with the second event occurring after a time of 1.70s. In a second frame S' moving relative to S, the second event is observed to occur after a time of 2.25 s. What is the difference Δx...

Homework Statement In frame F there are two lights on the x-axis at D and -D (D=0.6x10^9 m ) which flash simultaneously when t=0. There is another frame F' which moves at v=0.8c in standard configuration with F. I need to work out when observers standing at the origin of both frame F and F'...

Homework Statement Lets say that Planet A and Planet B are moving in the the same inertial reference frame. The distance between them is 8.3 light minutes. Event A occurs on Planet A at t=0, and Event B occurs on Planet B at t=2 minutes. If an observer is traveling from Planet A to B at 0.8c...

I'm studying special relativity and I'm having difficulty in understanding somethings. I have 2 questions I'm confused about. 1) If I am moving in relation to you, when you observe me, I should be in slow-motion. but you are moving in relation to me, so when I observe you, will you be in slow...

Hello, I was wondering if the following idea had been proposed in one form or another within a scientific community. Provided that the space within the singularity is dimensionless, that being 0 in length on all the axes (is it?) the following is in order. From this follows that the Planck's...

Homework Statement Prove that for a timelike interval, two events can never be considered to occur simultaneously. Homework Equations Δs'2=∆s'2 (∆s is invariant) s2=x2 - (ct)2 s'2=x'2 - (ct')2 The Attempt at a Solution I first imagined a reference frame K in which two...

Homework Statement E1 and E2 are two independent events. The probabilities of an error in judgement by a person regarding E1 and E2 are 0.02 and 0.05 respectively. Find the probability that the person will take the correct decision regarding : only one event Homework Equations Two events...

Homework Statement A foreign fishing submarine moves straight north through Canadian waters at a constant velocity of 12 m/s and a constant depth of 150m below the surface. A Canadian helicopter is in pursuit, flying in exactly the same direction at a constant velocity of 52 m/s and a constant...

3 earthquakes happened on day 15, 16, and 17. During these days, a temperature increase was observed apparently because of the earthquakes. But temperature also increases on other days. So, we don't know for sure if the temperature increase was triggered by the earthquakes or not, -maybe it...

Homework Statement Given two events, A and B, state why each of the following is not possible. Use formulas or equations to illustrate your answer. d. P(B) = 0.24 and P(B|A) = 0.32 Homework Equations P(A ∩ B) = P(A) * P(B|A) P(B|A)= (P(A ∩ B))/P(A) P(A|B)= (P(A ∩ B))/P(B) The...

As we know, the gravitational pull of the black hole is too strong, not even light can escape from it... Let me assume 2 person: A and B A is sucked into a black hole while B is outside the event horizon... At first, B will notice that A has disappeared due to the lights(image) of A is...

Hi Guys. I would like to ask what is the very nature of event in the same moment given a vast distances. Considering Point A (earth)-vast distance-Point B (galaxies). Would be possible that the event we're observing already happened long before it reaches us and may not exist at this very...

Homework Statement What is the minimum number of points a sample space must contain in order that there exists n independent events A_1, ..., A_n , none of which has probability zero or one? Homework Equations None at this time The Attempt at a Solution I was thinking that if each A_i...

Homework Statement This isn't actually a homework question, I'm reviewing for a midterm I have coming up this week and came across this question in some of the practice exercises that were provided. Let A,B,C be three events. Suppose that A and B are independent, B and C are mutually...

Homework Statement I have written everything in the attachement, please read it Homework Equations I have written everything in the attachement, please read it all of them :) The Attempt at a Solution My solution is also at the PDF attached, just check for correctness, and if i...

Homework Statement A Nova is a sudden, brief brightening of a star. Suppose Earth astronomers see two novas occur simultaneously, one in the constellation Orion and the other in the constellation Lyra. Both nova are the same distance from Earth, 2.5 E 3 c.y (lightyear) and are in exactly...

Homework Statement I will use an example to showcase my confusion: Suppose a person watches show A 2/3 of the time, show B 1/2 of the time, and both show A and show B 1/3 of the time. For a randomly selected day, what is the probability that the person watches only show A? For a randomly...

Hello, How can I convert the number of events + the luminosity in a cross section? I think this must be trivial... thanks..

Homework Statement Toss a pair of fair dice, one in red and the other is blue. Define the events A={Red dice showing 1 or 2 or 3} B={Red dice showing 3 or 4 or 5} C={The sum of points on the two dice equals 9} Are the 3 events pairwise independent? mutually independent? Justify your answer...

Homework Statement Find a system K' in which the following events in frame K appear at the same time: i) x1 = a; t1 = (2a) / c; y1 = 0; z1 = 0 ii) x2 = 2a; t2 = (3a) / (2c); y2 = 0; z2 = 0 Describe the motion of K'. Homework Equations Lorentz transformations; time dilation...

if an event happens at the exact moment of another for a single observer, what does instantaneous mean? This stems from a question i posed about the speed at which two entangled particles collapse into one definite state when one is measured. It got m thinking what does zero time and...

Homework Statement When David goes fishing the probability of him catching a fish of type A is 0.45, catching a fish of type B is 0.75 and catching a fish of type C is 0.2. David catches four fish. If the event X is David catching two fish of type A and two other fish, the event Y is David...

Homework Statement Suppose that two events occur in an hour, and the probability is uniformly distributed. If the time that the first event occurs has the same distribution as the time that the second event occurs, and the two distributions are independent, what is the probability that the...

Given three characters that have a specific probability assigned to each of them: Ω: .2 θ: .3 β: .4 What is the probability of having, say a sequence of 6 of these characters where the first and last character is a θ?

Hello. So I'm wondering if there is a way to assign a probability to a certain event in the code. Let's say that I want a certain arithmetic operation to have an 80% chance of happening (and make an if/else if statement based on that, or something similar...) Is there something in the...