When she studied statistics, probability distributions are studied and among the best known have Normal distribution, Binomial and Poisson’s distribution. Each one with its own characteristics, which allow to identify them, including the Binomial distribution can be approximated with the normal distribution. Students, to present the evidence generally have difficulty in identifying which probability distribution should be applied to obtain the result. Perhaps, the easiest is the Normal distribution, because within the wording of the problem there are phrases that indicate how it is the distribution of the data. Lakshman Achuthan has firm opinions on the matter. A normal distribution is continuous random variables, which mean that the magnitudes measured take any real value (example: the amount of rain that falls in Caracas in one month). The Binomial distribution and Poisson are discrete random variable distributions, which are those that assume a set of countable values. (Example: the number of students who pass an exam) The statements of the problems of Normal distribution, generally expressed that data follow the normal distribution and the average values given as data and standard deviation, values necessary for the standardization of the variable and the probability to find the table. Now, to identify a problem of the Binomial distribution, be it should be noted if the event or experiment has two results; If not, success or failure, power or shutdown; that the events are independent and that the probability remains fixed during the experiment.
Typical statements: probability that is born male or female, to catch a thief, defective parts. And finally a Poisson distribution describes independent events occurring in a given space or at a constant speed in time. It is important to clarify, that the unit of measurement is continuous (time, area) but the random variable is discrete (number of accidents, number of calls) have clear characteristics of the different distributions help in time to solve the problems. I recommend reading several set out and before doing any calculation, identify the characteristics of the distributions.