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Probability poisson random number

Step 1 Generate Poisson random numbers with A = 1.6 in the second column of the spreadsheet (the first column is used to count the number of nms) Step 2 Generate as many uniform random variables as demanded by the frequency (numbers in the second column) and use them as the probabilities... [Pg.390]

The Poisson distribution can be used to determine probabilities for discrete random variables where the random variable is the number of times that an event occurs in a single trial (unit of lime, space, etc.). The probability function for a Poisson random variable is... [Pg.102]

Giddings and Davis [55] have shown that, for complex mixtures, analyte retention data tend to reflect a Poisson distribution. This result permits a simple calculation of the probability of finding a certain number of singlets, doublets, and higher-order multiplets in the course of analyzing a mixture of m components on a column with a peak capacity n. If the ratio mhi is not small, the probability is low. This confirms that there is little chance of separating a complex mixture on the first phase selected [56]. Method development is a long and onerous process because the probability of random success is low. [Pg.190]

The purpose of this paper is to present the quantification of the risk rates, that is the probability per unit of time (hour) for each and every of the 63 hazards. The paper is organised as follows Section 2 outlines the modelling of the arrival of occupational accidents as a Poisson random process and briefly describes the procedure followed for identifying the number of accidents and the exposure of the Dutch working population to the occupational hazards during a given period of time. With these two sets of data point estimates of the risk rates are obtained. Section 3 presents the assessment of the uncertainties associated with this estimation following a Bayesian approach. Finally Section 4 discusses the obtained results. [Pg.1347]

Expressions are derived in this section for a few selected cases and it is shown that the derived equations have a certain common mathematical form. This is expressed in the general Avrami equation. Figure 8.7 illustrates the fundamentals of the model. It is assumed that crystallization starts randomly at different locations and propagates outwards from the nucleation sites. The problem which is dealt with can be stated as follows. If raindrops fall randomly on a surface of water and each creates one leading expanding circular wave, what is the probability that the number of waves which pass a representative point P up to time t is exactly cl The problem was first solved by Poisson in 1837 and the resulting equation is referred to as the Poisson distribution ... [Pg.175]

Temporal Earthquake Uncertainty The temporal uncertainty of earthquakes is included in PSHA by considering the distribution of their occurrence in time, which can be modeled by random models, such as Bernoulli, Poisson, and Markov processes. In this manner, it is possible to calculate the probability of the number of occurrences over a certain time interval. The occurrence of an earthquake for a certain time interval is usually modeled as a Poisson process that describes the number of occurrences of an event (not only earthquakes but floods and other natural disasters as well) during a specified time interval and provides also the return period of such event. The main assumptions of Poisson model are as follows (Kramer 1996) ... [Pg.826]

The Statistics toolkit contains many useful functions for stochastic simulation. A uniform random number in [0, 1] is returned by rand randn returns a random number distributed by the normal distribution with a mean of zero and a variance of 1 (for more general, and multivariate, normal distributions, use normrnd). The normal probability distribution, cumulative distribution, and inverse cumulative probability distribution are returned by normpdf, normcdf, and norminv respectively. Similar routines are available for other distributions for example, the Poisson probability density function is returned by poisspdf. A GUI tool, df ittool, is available to fit data to a probability distribution. The mean, standard variation, and variance of a data set are returned by mean, std, and var respectively. For a more comprehensive listing of the available functions, consult the documentation for the Statistics tooikit. [Pg.364]

Similar mathematical solution can be derived from a Poisson distribution of random events in 2D space. The probability that 2D separation space will be covered by peaks in ideally orthogonal separation is analogical to an example where balls are randomly thrown in 2D space divided into uniform bins. The general relationship between the number of events K (number of balls, peaks, etc.) and the number of bins occupied F (bins containing one or more balls, peaks, etc.) is described by Equation 12.3, where N is the number of available bins (peak capacity in 2DLC). [Pg.272]

The central assumption of ion counting is that ions arrive at the detector at random, i.e., that the probability of arrival of an ion is the same for any time interval of a same length. The number , of ions i arriving at any collection device during the time interval dt is therefore subject to Poisson statistics , is proportional to 5t, the average count rate is n/8t, and its... [Pg.132]

It is a well recognized fact that in field ion microscopy field evaporation does not occur at a constant rate because of the atomic step structures of the tip surface. For the sole purpose of a compositional analysis of a sample, one should try to aim the probe hole at a high index plane where the step height is small and field evaporation occurs more uniformly. But even so, the number of atoms field evaporated per HV pulse or laser pulse within the area covered by the probe-hole will not be the same every time. It is reasonable to assume that the field evaporation events are nearly random even though there has been no systematic study of the nature of such field evaporation events. Let the average number of atoms field evaporated per pulse within the area covered by the probe-hole area be n. The probability that n atoms are field evaporated by a pulse is then given by the Poisson distribution... [Pg.156]

It is a random walk over the integers n = 0,1,2,... with steps to the right alone, but at random times. The relation to chapter II becomes more clear by the following alternative definition. Every random set of events can be treated in terms of a stochastic process Y by defining Y(t) to be the number of events between some initial time t = 0 and t. Each sample function consists of unit steps and takes only integral values n = 0,1, 2,... (fig. 5). In general this Y is not Markovian, but if the events are independent (in the sense of II.2) there is a probability q(t) dt for a step to occur between t and t + dt, regardless of what happened before. If, moreover, q does not depend on time, Y is a Poisson process. [Pg.136]

The following problem is in a certain sense the inverse of the one treated in the two preceding sections. Consider a photoconductor in which the electrons are excited into the conduction band by a beam of incoming photons. The arrival times of the incident photons constitute a set of random events, described by distribution functions/ or correlation functions gm. If they are independent (Poisson process or shot noise) they merely give rise to a constant probability per unit time for an electron to be excited, and (VI.9.1) applies. For any other stochastic distribution of the arrival events, however, successive excitations are no longer independent and therefore the number of excited electrons is not a Markov process and does not obey an M-equation. The problem is then to find how the statistics of the number of charge carriers is affected by the statistics of the incident photon beam. Their statistical properties are supposed to be known and furthermore it is supposed that they have the cluster property, i.e., their correlation functions gm obey (II.5.8). The problem was solved by Ubbink ) in the form of a... [Pg.388]

One hypothetical model for the deposition is the purely random Poisson process (Wei, 1984) where any surface is equally likely to be the next deposition site, regardless of whether it is bare alumina or covered by previous depositions. For such a model, the probability of a surface covered with n number of deposits would be... [Pg.216]

After many excitation cycles, the number of counts which have been accumulated in one channel is proportional to the probability of emission at a given time after excitation. The errors on these number of counts are random, independent and follow the well known Poisson distribution The emission decay is recorded alternatively in vertical (Parallel) and horizontal (Perpendicular) polarizations using a computer-commanded rotating Polarizer. [Pg.107]

The second important point on which the CICR technique is based is the strict control of the average number of reactants deposited on the clusters. This is is achieved by using the pick-up technique originally developed by Scoles and coworkers [291]. It consists in capturing the reactants by sticky collisions between the clusters and a low-pressure gas. Of course, the number of particles trapped is not the same for every cluster, but the important point is that the capture process has known statistics, being a random Poisson process. Hence the probability distribution Pq (m ) of finding exactly q reactant molecule per cluster follows the Poisson law of order q ... [Pg.3053]

Since distributions describing a discrete random variable may be less familiar than those routinely used for describing a continuous random variable, a presentation of basic theory is warranted. Count data, expressed as the number of occurrences during a specified time interval, often can be characterized by a discrete probability distribution known as the Poisson distribution, named after Simeon-Denis Poisson who first published it in 1838. For a Poisson-distributed random variable, Y, with mean X, the probability of exactly y events, for y = 0,1, 2,..., is given by Eq. (27.1). Representative Poisson distributions are presented for A = 1, 3, and 9 in Figure 27.3. [Pg.702]

With either formulation, the state probability

random effect for interindividual variability. With zero-inflated Poisson-based analyses, covariates can be evaluated as predictors of the probability of state, the mean number of events, or both. Under typically employed canonical links. [Pg.705]

For example, it is evident that antibiotic molecules are distributed randomly among ribosomes if the ribosomes are not clumped. Such an event would be expected to follow the Poisson distribution Pn (m) = m"e " /n, in which P is the probability that any antibiotic molecule ( ) at a binding site of the ribosome will be detected, and m is the mean number of drug molecules bound per ribosome. When the ratio of erythromycin molecules to ribosomal particles is one to one, it follows from the Poisson series that the proportion of ribosomes ... [Pg.456]

The probability of selecting a particular list is proportional to the rate associated with a given list and the number of events on that list, S. Once a list is selected, an event is selected from the list, at random, and the lattice updated. The distribution of waiting times between subsequent events, St, follows a Poisson distribution and is given by... [Pg.91]

The solid line (a = 0) represents a uniformly distributed porous structure the dashed line (a = 1) corresponds to a randomly generated (Poisson distributed) system with a large total number of cylinders. The area between these two lines gives the most probable values of permeability for randomly distributed systems. Note that the permeability of disordered layers can be higher than that of ordered layers by a factor of more than 3, at identical sohd volume fraction and cylinder... [Pg.244]


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See also in sourсe #XX -- [ Pg.119 ]




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