Sampling Definition and 190 Threads

I want to use this method to evaluate a triple integral that is otherwise impossible (not elementary). The region is the unit sphere. The Monte Carlo method sounds simple, but if I were to use MATLAB to do this, how would I pick my random sample points so that they are INSIDE the region...

I used Audacity to generate a 5500Hz tone at a sampling rate of 11025. This is the result: To me this appears to be a tone at a frequency of (11025/2) with oscillating amplitude rather than a frequency of 5500. The tone also sounds like it looks. It has audible oscillations in amplitude. At...

Hey guys, I'm just curious to know, why is it important to sample the air above and the water in the swimming pool for the chlorine level...and I mean, is there a technique which involves potassium iodide and a pipette? Thanks!

Hi, I tried sampling s(t)=sin(400\pi t) + 0.5cos(12000\pi t) at 10000Hz (below the Nyquist sampling rate) in MATLAB and plotted the spectrum, I found that it had frequencies at +-200Hz (same as the continuous signal version) and +- 4000Hz(instead of 6000Hz in the...

Homework Statement x(t) = 3*sin(1000*pi*t) Suppose that the signal is sampled at a rate of fs = 2000Hz. What is the discrete time signal obtained after sampling (i.e., the signal expressed as a function of sample number n, x[n]) What discrete time frequency, f-hat will the signal x[n]...

Homework Statement A sample survey interviews an SRS of 267 college women. Suppose (as is roughly true) that 70% of all college women have been on a diet within the past 12 months. Use a Normal approximation to find the probability that 75% or more of the women in the sample have been on a...

Homework Statement Given a ramp function x(t) = t*heaviside(t) with the known z-transform ( z / (z-1)^2 ). If the time-domain signal has been delayed by 2 seconds, then sampled with an unknown sampling rate (T). How could I get the z-transform (one-sided) for the discrete signal, for any values...

I have been puzzling over this problem for about a week now and cannot find the answer. In my opinion it is very theoretical, but I know I ma not the best mathematician on here so maybe someone else could look at this. Thank you.

hello everyone, I have an exam question about sampling frequency. Actually i really don't get the concept. I have limited sources. Question: Bandwith of x(t) 10 kHz y(t) obtained modulating x(t) with a sinus wave with frequency 30 kHz. y(t) sampled a) What is the sampling frequency...

Hi! I'm trying to write an algorithm that performes Importance Sampling Monte Carlo integration. I found some info about it, but I have trouble understanding how it actually can be implemented. Let f(x) be the function we want to integrate and p(x) the non-uniform probability...

The Fair Sampling Assumption, as commonly discussed, is implicit in Bell tests: As long as detection efficiency is less than 100%, the observed photon pairs are a representative sample of the total universe of emitted pairs. At this time, no Bell test has satisfactorily closed both the Fair...

Hi, y'all! I'm trying to figure out how to do this MATLAB project for school. We're required to read in an image and then sample random regions(square, matrix-shaped) of it. I read in the image and it is formed by a lot of numbers(pixels?), and I determined how to generate a random...

I am wondering why there are no discussions about correctness of fair sampling assumption in photon entanglement experiments so I would like to start one. Bell's inequalities are derived considering all emitted particles. But in real photon entanglement experiments only portion of emitted...

Okie, I am confused. What is the difference between Variance of Sampling Distribution VS Sample Variance? Let me take a shot first... 1.) Sample Variance is just the variance of the sample, like u have 5 objects from a pool of 1000 objects... the sample variance is just the variance of the...

Homework Statement A box contains 5 keys, only one of which will open a lock. Keys are randomly selected and tried, one at a time, until the lock is opened (keys that do not work are discarded before another is tried). Let Y be the number of the trial on which the lock is opened. What is the...

Why is the frequency spectrum of a sampled signal replicated? We have a Low pass filtered signal sampled well above nyquist rate. I can't understand why the spectrum is replicated.

Okay... this is a really simple question but I am pratically going nuts over it I can't sleep, I've been looking at it for like 12 hours, googling and wiking over it I am going crazy... Okie... Suppose I have 4 numbers, 0, 2, 4 and 6 and I grab 2 random ones with replacement... so I have...

Can we synchronize n samplers so that the system is being sampled at 1/n Planck time? What could we tell about the data values between two adjacent samples?

Hello, I have a question regarding fft's. My experience with working with Fourier transforms is pretty much limited to transforming contrived functions pen and paper style. But now I need something and I think the fft is the appropriate tool, but I'm having a hard time understanding some...

Hi, I have a project due that has to be done in Simulink. I am somewhat familiar with Simulink, but some things don't make sense to me. First off, What determines the time step between each iteration? eg. when you have a clock in the model, what determines the change in time from one...

Homework Statement Let X1,X2,...X10 be independent normal random variables with mean 10 and std dev 4. Let Y = X1+X2+...+X10. Let X be Y/10. What is P(X < 8) Homework Equations E(X) = 10 and Var(X) = 42 / 10 = 1.6 std dev of X = 1.6.5 = 1.26 The Attempt at a Solution To convert...

How come these two functions are used interchangebly? A sampling function is supposed to be a square wave with a very small duty cycle, but at least the height is still finite. A delta function has infinite height and zero width. It seems like both square wave and dirac train are used as...

Let's say we have a given probability distribution. We sample two random numbers from this distribution, say x1 and x2. What is the probability that x1 > x2? Is it always 0.5? Does it even depend on the distribution? Sorry if it appears trivial. I just can't seem to wrap my mind around this...

Hi, I am struggling with a problem and do not know how I should approach it. I went to a baseball game with my son, where I bought him a packet of M&Ms. While eating the candy, my son asked me what color most of the M&Ms are. At first, I intended to tell him that there are equal numbers...

http://s188.photobucket.com/albums/z65/liznbren/stuff/?action=view&current=envelope.jpg" If I sample at just fractionally above the Nyquist rate, and I obtain a sequence as is shown in the linked image, is it reasonable to expect perfect interpolation (say with a Sinc function ideally) as it...

The process known as sampling in reference to music is as follows: A device called a sampler is used to convert an analog signal representing sound waves into digital information. This digital information is called a sample, artists often use samples in their music. however, this not the only...

Can someone define the process of digital sampling for me, perhaps a website with some info on it. I'm writing a term paper and I keep running into sampler adds, but no concrete facts. What is the function of sampler? I'm referring to a device that turns an analog recording into a digital...

I understand that it was Nyquist who proved that a channel of bandwidth B can transmit at a baud rate of 2B. Also, Shannon, about 10 years later showed that if a signal is sampled at a rate of at least 2B, where B is the bandwidth of the bandlimited signal, then the signal can be reconstructed...

Hello, This is the same type of question as the one I just posted before. This time I have obtained an answer and would really appreciate it if someone would check my reasoning: Suppose a signal x(t) has a Nyquist sampling frequency \omega_s . Compute the Nyquist sampling frequency for the...

Here's my question: Suppose a signal x(t) has a Nyquist sampling frequency \omega_s. Compute the Nyquist sampling frequency for the following signal in terms of \omega_s: x(t) + x(t-1) Well my first thought was, let's see how the spectrum of this new signal compares to that of the...

We are considering a system in which the input signal x(t) is multiplied by a periodic square wave s(t) in order to produce an output w(t). The input signal is band limited with |X(j\omega)| = 0 \ \ \textrm{for} \ \ |\omega| \geq \omega_M , where \omega_M is the bandwidth. We are supposed...

Hiya guys, I just have what I'm sure is a simple question about statistics, but I can't seem to find it anywhere ... I was wondering, when finding the standard deviation of a sample mean, why do you divide the population standard deviation by the square root of n? I'm not really sure why...

I need some online source . explaining how do we take a DNA sample from body cells.Preferably in a more advanced language .

The Sampling Theorem states that when you have a signal x(t) bandlimited to B Hz, then if you sample the signal at frequency f_s higher than or equal to 2B, then you can use the sample to reconstruct the original signal x(t) uniquely. Yet, if you consider the simple sinusoidal signal...

The marketing manager of humber marketing tests new sales strategy by randomly selecting 250 consumers with a gross income less than $50000, and 250 consumers with a gross income more than 50000. this type of samping is an example of: a) cluster sampling b) convenience sampling c)...

You are on the staff at the Post Office. Your job is to find a process to find the average waiting time for service. How do you collect the data, and once it is collected, what do you do next?

Hi All I am hoping someone can help me out with my problem. I am sampling data from a flow meter every 10 seconds and storing it into a data historian. The readings are the instantaneous flow rate at the moment the data is sampled. My problem is that I need to work out (based on the stored...

Edit: Moved from statistics - https://www.physicsforums.com/showthread.php?s=&postid=164120#post164120 I'm doing some homework over the break (!) so I don't have access to my usual lines of help. I've hit a wall: I don't really know how to solve a problem like this, from the...

I'm doing some homework over the break (!) so I don't have access to my usual lines of help. I've hit a wall: I assume the "N(12.2, .04)" notation refers to that the distribution of the boxes has mean 12.2 and variance .04. I think 'a' has something to do with the normal distribution, how...

The mean probability of 100 observations is .0422. If you are not given the data for a sample size of 200, how do you find the mean probability of this data using the mean probability you found from .0422? thanks