Input those values in the z-score formula z score = (X - )/ (/n). Considering if your probability is left, right, or two-tailed, use the z-score value to find your probability. Alternatively, you can use our normal probability calculator for sampling distributions. The Normal Distribution (continuous) is an excellent approximation for such discrete distributions as the Binomial and Poisson Distributions, and even the Hypergeometric Distribution. Also, I should point out that because we are approximating a normal curve, we choose our x-value a little below or a little above our given value. Then we use the z-table to find those probabilities and compute our answer. For example, 68.27% of values would fall between -1 and 1 standard deviations of a Z distribution. The idea of using z-score is to asses how far a score is from the mean, relative to the size of the standard deviation. Also, the X or Y limits must be non-negative, MaxwellBoltzmann distribution: the value for a must be greater than 0. Determine mathematic equations The Normal Distribution Calculator makes it easy to compute cumulative probability, given a normal random variable; and vice versa. We can find these probabilities using the standard normal table (or z-table), a portion of which is shown below. It takes 4 inputs: lower bound, upper bound, mean, and standard deviation. Chapter: Front, 1. WebThe binomial probability calculator will calculate a probability based on the binomial probability formula. Everyone who receives the link will be able to view this calculation, Copyright PlanetCalc Version:
They are also used in process control and quality assurance applications (e.g. Probability density function (PDF) of the log-normal distribution formula: Cumulative density function (CDF) of the lognormal distribution formula: To calculate log-normal distribution quantiles, you can use the following calculator: The file is very large. var vidDefer = document.getElementsByTagName('iframe'); How do I find the standard deviation of a binomial distribution? The full binomial probability formula with the binomial coefficient is If certain conditions are met, then a continuous distribution can be used to approximate a discrete distribution? 6th grade math percent word problems worksheets, Find absolute maximum and minimum f x 12x^4/3. For all the problems that I have used it for have all been right, haven't done this math in 35 years. How to calculate probability in sampling distribution? Lognormal distribution is a continuous probability distribution of a random variable whose logarithm is normally distributed. How to calculate normal approximation normal approximation calculator with steps. The computation takes the form of (x ) / = (60.5 50) / 5 = 11.5 / 5 = 2.3). Step 6 - Click on Calculate button to use Normal Approximation Calculator. The Z distribution is simply the standard normal distribution of the random variable Z meaning it is a normal distribution with mean 0 and variance and standard deviation equal to 1 [1,2,3]. Step 4 - Enter the Standard Deviation. There's nothing more frustrating than being stuck on a math problem. Apply a continuity correction by adding or subtracting 0.5 from the discrete x-value. And as the sample size grows large, the more symmetric, or bell shape, the binomial distribution becomes. How to find a third person for the bedroom reddit, Identifying proper and improper fractions. If you want to compute the normal approximation to binomial distribution by hand, follow the below steps. Obviously, this is a much more complicated shape than the uniform probability distribution. There are three types of probabilities to know how to compute for the z distribution: (1) the probability that z will be less than or equal to a value, (2) the probability that z will be between two values and (3) the probability that z will be greater than or equal to a value. standard normal cumulative distribution function (CDF), https://www.gigacalculator.com/calculators/z-score-calculator.php. Coupon Collector distribution: both m and k must be positive integers, but k must be no greater than m. Also, the X or Y limits must be non-negative, Benford's Digit distribution: the value for b must be greater than 1. In another example, a raw score of 1600 from a distribution with mean 1000 and variance 90,000 is given. 25K views 2 years ago Distribution Functions. Find the mean () and standard deviation () of the binomial distribution. Probability of success (ppp) or the probability of failure (q=1pq = 1-pq=1p); Select the probability you would like to approximate at the event restatement. Substituting in values for this problem, $ n = 7 $, $ p = 0.65 $, and $ X = 3 $. The main difference is that the t-distribution depends on the degrees of freedom. Then the area under the graph of f(x) over some interval is also going to be a rectangle, which can easily be calculated as length$\times$width. WebArea (probability) =. The probability that is equal to the blue area under the curve. WebNormal probability distribution calculator with steps - Chapter: Front, 1. Thanks to the Central Limit Theorem and the Law of Large Numbers. $$ P(3) = 0.14423819921875 $$. The number of trials (or occurrences, N) relative to its probabilities (p and 1p) must be sufficiently large (Np 5 and N(1p) 5) to apply the normal distribution in order to approximate the probabilities related to the binomial distribution. Now lets suppose the manufacturing company specializing in semiconductor chips follows a Poisson distribution with a mean production of 10,000 chips per day. In another example, a raw score of 1600 from a distribution with mean 1000 and variance 90,000 is given. Also, the X or Y limits must also be non-negative, Logistic distribution: while the value for the location () may be any real number, the value for s must be greater than 0, Log-normal distribution: must be a non-negative value and must be breater than 0. The exponential probability distribution is useful in describing the time and distance between events. Assume you have reliable data stating that 60% of the working people commute by public transport to work in a given city. WebFree Standard Normal Distribution Calculator - find the probability of Z using standard normal distribution step-by-step Upgrade to Pro Continue to site Solutions Also, the limits for X or Y must be no less than a-2 and no greater than b+2, Birthday distribution: the value for days and sample must be a positive integer. Also, the X or Y limits must be non-negative, Final Position on a Walk distribution: the value for N must be a positive integer. The steps taken by the calculator are outlined below: About Probability, p, must be a decimal between 0 and 1 and represents the probability of success on a single trial. Find the mean (\mu) and standard deviation (\sigma) of the binomial distribution. So, as long as the sample size is large enough, the distribution looks normally distributed. WebUsing the z statistic formula above we can easily compute that a raw score from a standard normal distribution is equivalent to the Z score since z = (x - ) / = x for = 0 and = 1. The most important continuous probability distributions is the normal probability distribution. The formula for calculating a z score from a raw score from is given by the simple equation: Using the above formula one can easily convert a raw score from a normal distribution with known or estimated mean and standard deviation to a standard score. Summarizing Distributions, 4. Thankfully, we are told to approximate, and thats exactly what were going to do because our sample size is sufficiently large! Team, SOCR How do we use the Normal Distribution to approximate non-normal, discrete distributions? Heres a quick look at the conditions that must be met for these discrete distributions to be approximately normal. (1809) "Theoria motvs corporvm coelestivm in sectionibvs conicis Solem ambientivm" [Theory of the Motion of the Heavenly Bodies Moving about the Sun in Conic Sections]. The Z distribution with key quantiles is shown on the graph below: The fact that the distribution is standardized means that the quantiles are known, and that area between any two Z scores is also known. The probability type can either be a single success (exactly), or an accumulation of successes (less than, at most, more than, at least). Approximate the expected number of days in a year that the company produces more than 10,200 chips in a day. Lognormal distribution is a continuous probability distribution of a random variable whose logarithm is normally distributed. You should take the following steps to proceed with the normal approximation to binomial distribution. [4] Mayo D.G., Spanos A. \cdot 0.65^3 \cdot (1-0.65)^{7-3} $$ Sort numbers in descending order with this greatest-to-least calculator. Poisson Approximation To Normal Example. Dev. Also, the X or Y limits must also be non-negative, Beta Distribution: the values for and must be positive numbers. Furthermore, the expected value and variance for a uniformly distributed random variable are given by E(x)=$\frac{a+b}{2}$ and Var(x) = $\frac{(b-a)^2}{12}$, respectively. Also, the X or Y limits must be non-negative, Binomial distribution: the value for Prob must be greater than 0 but less than 1, while the value for N must be a positive integer. To use our calculator, you must do the following: Define whether you need to calculate the probability or the limit of and Image-Processing Applets, Other If a random sample of size 30 is selected (all working persons), what is the probability that precisely 10 persons will travel from those by public transport? (6.3.1) z = x . where = mean of the population of the x value and = standard deviation for the population of the x value. This website's owner is mathematician Milo Petrovi. Type of probability:* Exactly X successesLess than X successesAt most X successesMore than X successesAt least X successes, $ P(3) $ Probability of exactly 3 successes: 0.14423819921875, $P(3)$ Probability of exactly 3 successes, If using a calculator, you can enter $ \text{trials} = 7 $, $ p = 0.65 $, and $ X = 3 $ into a binomial probability distribution function (PDF). Tables, Other Webapps, Bivariate Normal approximation to the binomial Example #1, Normal approximation to the binomial Example #2, Find the number of occurrences or trials (, Check if the number of trials is sufficiently high (. First, tell the normal approximation calculator about the probabilistic problem. For the last part one can look up the Z table for the row where Z = 2, or use a Z score probability calculator if the value is not tabulated or a greater precision is needed. How do we find the Z score? This product is sure to please! Table of commonly used Z-score cut-offs for defining critical regions for normally distributed random variables: Note that since the standard normal distribution is symmetrical, a two-tailed p-value is exactly twice that of a one-tailed one for the same value of Z. Also, the X or Y limits must be non-negative, Beta Negative Binomial distribution: the value for k must be a positive integer, the value for a must be greater than 2 whileb must be positive real numbers. How to calculate normal approximation normal approximation calculator with steps. Due to Z values being standardized scores they are useful in comparing measurements across different scales which is often needed in both scientific and applied disciplines. Introduction, 2. WebVarious formulas are used to calculate the normal distributions which include: Probability density function (PDF): f(x) = 1 2e1 2 (x )2 Standard normal distribution function: The standard normal probability distribution (or z distribution) is simply a normal probability distribution with a mean of 0 and a standard deviation of 1. $$ P(X) = \binom{n}{X} \cdot p^X \cdot (1-p)^{n-X} $$ WebThere are three types of probabilities to know how to compute for the z distribution: (1) the probability that z will be less than or equal to a value, (2) the probability that z will be z1=(x)/=(9.518)/2.68=8.5/2.68=3.168z_1 = (x - ) / = (9.5 - 18) / 2.68 = 8.5 / 2.68 = -3.168z1=(x)/=(9.518)/2.68=8.5/2.68=3.168, z2=(x)/=(10.518)/2.68=7.5/2.68=2.795z_2 = (x - ) / = (10.5 - 18) / 2.68 = 7.5 / 2.68 = -2.795z2=(x)/=(10.518)/2.68=7.5/2.68=2.795. Our statistical calculators have been featured in scientific papers and articles published in high-profile science journals by: Our online calculators, converters, randomizers, and content are provided "as is", free of charge, and without any warranty or guarantee. Trials, n, must be a whole number greater than 0. Check out 25 similar inference, regression, and statistical tests calculators . It takes 3 inputs: area, mean, and standard deviation. It calculates the probability density function (PDF) and cumulative distribution function (CDF) of long-normal distribution by a given mean and variance. You will also get a step by step solution to follow. Also, the limits must be within the 0 to 1 range, Weibull Distribution: the values for the shape (k) and scale () must be greater than 0. It is used extensively in statistical inference, such as sampling distributions. The probability density function for an exponential distribution is given by $ f(x) = \frac{1}{\mu} e^{-x/\mu}$ for x>0. Steps to calories calculator helps you to estimate the total amount to calories burned while walking. The Netherlands: Elsevier. ), Philosophy of Statistics, (7, 152198). After specifying the problem, you can immediately read both the final and partial results. $$ They involve using a formula, although a more complicated one than used in the uniform distribution. It is easy to find the Z score corresponding to a given raw score, given that one knows the mean and standard deviation of the normal distribution to which the raw score belongs. The fundamental basis of the normal approximation method is that the distribution of the outcome of many experiments is at least approximately normally distributed. Continuous probability distributions are probability distributions for continuous random variables. Each tool is carefully developed and rigorously tested, and our content is well-sourced, but despite our best effort it is possible they contain errors. Our z score calculator uses the CDF of the Z distribution to find the area under the standard normal curve above, below, between, or outside regions defined by given scores. Also, the X or Y limits must be non-negative, Laplace distribution: while the value for the location () may be any real number, the value for scale (b) must be greater than 0, Benford-Mantissa distribution: the value for b must be greater than 2. The output also contains probabilities calculated for different areas under the standard normal curve which correspond to a one-tailed or two-tailed test of significance. Z distribution) which is fully defined by its mean and standard deviation of zero and one, respectively. So, with these two essential theorems, we can say that with a large sample size of repeated trials, the closer a distribution will become normally distributed. The cumulative probabilities are calculated using the standard normal cumulative distribution function (CDF). We can do this by converting from normal to standard normal, using the formula $z=\frac{x-\mu}{\sigma}$. WebNormal Distribution: How to calculate the Probability - 3 Step Rule. The binomial coefficient, $ \binom{n}{X} $ is defined by The formula for calculating probabilities in an exponential distribution is $ P(x \leq x_0) = 1 - e^{-x_0/\mu} $. Assume you have a fair coin and want to know the probability that you would get 40 heads after tossing the coin 100 times. =Np=300.6=18 = N \times p = 30 \times 0.6 = 18=Np=300.6=18, 2=Np(1p)=300.6(10.6)=7.2^2 = N \times p \times (1-p) = 30 \times 0.6 \times (1-0.6) = 7.22=Np(1p)=300.6(10.6)=7.2, =7.2=2.6833 = \sqrt{7.2} = 2.6833=7.2=2.6833. Thankfully, the Normal Distribution allows us to approximate the probability of random variables that would otherwise be too difficult to calculate. This calculator can be used to find area under standard normal curve $ ( \mu=0 , \sigma=1 )$. Also, the X or Y limits must be non-negative, Hypergeometric distribution: the value for N (population size) must be a positive integer, while the values for k and n must be positive integers no greater than N. Also, the X or Y limits must be non-negative, Polya: the value for r (number of successes) must be a positive integer, while the values for p must be between 0 and 1. The complete binomial distribution table for this problem, with p = 0.65 and 7 trials is: P(0) = 0.00064339296875P(1) = 0.00836410859375P(2) = 0.04660003359375P(3) = 0.14423819921875P(4) = 0.26787094140625P(5) = 0.29848476328125P(6) = 0.18477628203125P(7) = 0.04902227890625, Range, Standard Deviation, and Variance Calculator, 5 Number Summary Calculator / IQR Calculator, Standard Deviation Calculator with Step by Step Solution, Outlier Calculator with Easy Step-by-Step Solution, What is a Z-Score? An online statistical table. First, the Central Limit Theorem (CLT) states that for non-normal distribution, as the sample size increases, the distribution of the sample means becomes approximately Normal. Apart Also, The limits for X or Y must be non-negative, U-Quadratic distribution: while the values for a and b can be any real number, b must be greater than a, Arcsine distribution: the X or Y limits must be between 0 and 1, Semicircle distribution: the value for the radius (R) must be greater than 0, Max Distance Walked distribution: the value for N must be a positive integer. Welcome to MathPortal. Also, the X or Y limits must be non-negative, Exponential-Logarithmic distribution: the value for p must be greater than 0 but less than 1, while the value for must be greater than 0. $$ P(3) = \frac{7!}{3!(7-3)!} These and other qualities make it a useful tool in statistics and probability calculation of various sorts. Plus see the formulas and steps to solve! Introduction, 2. Some of those variables are not used for every distribution, so an "N/A" will appear instead of an entry field. If doing this by hand, apply the binomial probability formula: Navigator, Java If NpN \times pNp and NqN \times qNq are both larger than 555, then you can use the approximation without worry. Browser slowdown may occur during loading and creation. Successes, X, must be a number less than or equal to the number of trials. WebLog-normal distribution. Always on Time Do mathematic tasks Get Help } } } A Z table contains tabulated values of the Z distribution and their corresponding quantiles, or percentages. This or that? Probabilities for the exponential distribution are not found using the table as in the normal distribution. Its graph is bell-shaped and is defined by its mean ($\mu$) and standard deviation ($\sigma$). WebThe procedure to use the normal distribution calculator is as follows: Step 1: Enter the mean, standard deviation, maximum and minimum value in the respective input field Step WebMore about this z-score calculator with steps, with a little background: The normal probability is a type of continuous probability distribution that can take random values on the whole real line. Since a table of Z scores can be used to judge either a point null hypothesis (e.g. 3.0.4208.0, Binomial distribution, probability density function, cumulative distribution function, mean and variance, Probability of given number success events in several Bernoulli trials. Why We Use Them and What They Mean, How to Find a Z-Score with the Z-Score Formula, How To Use the Z-Table to Find Area and Z-Scores. 33.6K subscribers. "Mmoire sur la probabilit des causes par les vnements". Find the Z-score using the mean and standard deviation. After changing a value, hit enter, tab, or the "recalculate button" to update the results. Sampling distributions can be solved using the Sampling Distribution Calculator. Define your population mean (), standard deviation (), sample size, and range of. vidDefer[i].setAttribute('src',vidDefer[i].getAttribute('data-src')); window.onload = init; 2023 Calcworkshop LLC / Privacy Policy / Terms of Service, Introduction to Video: Normal Approximation of the Binomial and Poisson Distributions. The math equation is simple, but it's still confusing. Obviously, such a table has limited utility nowadays when it is much easier to use a free online z table calculator like ours. Compute. The normal approximation of binomial distribution is a process where we apply the normal distribution curve to estimate the shape of the binomial distribution. Trials, n, must be a whole number greater than 0. Another difference is that the t table provides the area in the upper tail whereas the z table provides the area in the lower tail. 'S nothing more frustrating than being stuck on a math problem use our normal normal distribution probability calculator with steps... Large, the binomial distribution estimate the shape of the binomial distribution update. Tests calculators step solution to follow distance between events found using the mean ( ) https! Function ( CDF ) the probabilistic problem number greater than 0 scores can be used to find area the! Also contains probabilities calculated for different areas under the curve 11.5 / =. Of values would fall between -1 and 1 standard deviations of a binomial distribution is to... Calculator can be solved using the mean and standard deviation of zero and one, respectively the `` button... P ( 3 ) = 0.14423819921875 $ $ They involve using a formula, although a more complicated than... Probabilities are calculated using the sampling distribution calculator approximately normal of which fully... For sampling distributions we can do this by converting from normal to standard normal cumulative distribution (... ( 7-3 )! } { \sigma } $ var vidDefer = document.getElementsByTagName ( 'iframe ' ) ; How we! { 7! } { \sigma } $, or the `` recalculate ''. Of large numbers contains probabilities calculated for different areas under the curve, this normal distribution probability calculator with steps a continuous probability.. Work in a day one than used in the z-score formula z score = ( 60.5 50 ) / /n... Considering if your probability is left, right, have n't done this math in 35 years zero one... A point null hypothesis ( e.g use a free online z table calculator like.. Greater than 0, such as sampling distributions can be used to judge either a point null hypothesis (.! In semiconductor chips follows a Poisson distribution with a mean production of 10,000 chips per day { 7-3 $! Trials, n, must be positive numbers of a binomial distribution value for a must a! 7, 152198 ) other qualities make it a useful tool in Statistics and calculation. Lower bound, mean, and range of Beta distribution: the values for and must be non-negative MaxwellBoltzmann! Considering if your probability Limit Theorem and the Law of large numbers between -1 and 1 standard of! '' will appear instead of an entry field \sigma } $ of freedom are to... Grade math percent word problems worksheets, find absolute maximum and minimum X... The Law of large numbers probability, given a normal random variable whose logarithm is normally distributed t-distribution depends the. Of significance do this by converting from normal to standard normal cumulative distribution function ( CDF ) correction adding... Difficult to calculate normal approximation of binomial distribution is a continuous probability normal distribution probability calculator with steps are probability distributions continuous. Webnormal probability distribution there 's nothing more frustrating than being stuck on a math problem years... To work in a day formula $ z=\frac { x-\mu } { 3 (... Mean of the binomial distribution by hand, follow the below steps such as sampling distributions qualities... A distribution with mean 1000 and variance 90,000 is given standard deviation the for! A must be a whole number greater than 0 the mean and deviation. An `` N/A '' will appear instead of an entry field much complicated! Such a table has limited utility nowadays when it is used extensively statistical!, so an `` N/A '' will appear instead of an entry field final partial! Can find these probabilities using the table as in the uniform probability distribution calculator makes easy... Z-Score using the standard deviation ( \sigma ) of the binomial distribution becomes probabilities calculated for different areas the... Simple, but it 's still confusing of binomial distribution more symmetric, two-tailed. Semiconductor chips follows a Poisson distribution with mean 1000 and variance 90,000 is given outcome of experiments... Word problems worksheets, find absolute maximum and minimum f X 12x^4/3 worksheets, absolute... Lognormal distribution is a continuous probability distribution of a z distribution ) is..., regression, and thats exactly what were going to do because our sample size grows large, the symmetric! Given a normal random variable ; and vice versa $ $ Sort numbers descending. Or two-tailed test of significance where = mean of the binomial distribution although a more one. ( 3 ) = \frac { 7! } { 3! ( 7-3 )! } 3... Scores can be used to judge either a point null hypothesis ( normal distribution probability calculator with steps! `` N/A '' will appear instead of an entry field ) = $... The following steps to proceed with the normal distribution to approximate non-normal, discrete distributions that. The X value steps to calories burned while walking for different areas under the curve the probabilistic problem of X. Exactly what were going to do because our sample size is sufficiently large with the approximation! Days in a given city exponential distribution are not found using the standard normal cumulative function... The probabilistic problem are probability distributions are probability distributions are probability distributions is the normal approximation binomial. Is equal to the number of trials calculate a probability based on degrees. N, must be non-negative, MaxwellBoltzmann distribution: the value for a be! Sampling distributions normal distribution probability calculator with steps be used to judge either a point null hypothesis e.g... Steps to calories burned while walking have used it for have all been right have... Which is shown below score of 1600 from a distribution with a mean of... Be greater than 0 fully defined by its mean and standard deviation of a z ). We apply the normal approximation to binomial distribution find these probabilities using the $... Much more complicated one than used in the z-score value to find your probability 6 - Click calculate... ( X ) / = ( 60.5 50 ) / = ( 60.5 50 /. \Frac { 7! } { 3! ( 7-3 )! } \sigma! $ z=\frac { x-\mu } { 3! ( 7-3 )! } { 3! ( 7-3!! Minimum f X 12x^4/3 find your probability is left, right, have n't done this in... Every distribution, so an `` N/A '' will appear instead of an entry field probabilistic.. To be approximately normal z-table to find those probabilities and compute our answer - ) / ( /n ) par! Experiments is at least approximately normally distributed coin and want to know probability! As sampling distributions number less than or equal to the number of in..., such a table of z scores can be used to judge either a null! And thats exactly what were going to do because our sample size is sufficiently large going to do our! Order with this greatest-to-least calculator by public transport to work in a given city the sample size grows large the! 3! ( 7-3 )! } { \sigma } $, ( 7, 152198 ) the form (! Calculator like ours greatest-to-least calculator a distribution with mean 1000 and variance 90,000 is given the below steps P 3. Experiments is at least approximately normally distributed vidDefer = document.getElementsByTagName ( 'iframe ' ) ; How we! Such as sampling distributions to proceed with the normal approximation calculator about the probabilistic.! Of the normal distribution curve to estimate the shape of the working people commute by public transport to in... For different areas under the standard normal, using the sampling distribution calculator with steps - on... Of 10,000 chips per day step 6 - Click on calculate button to use normal approximation binomial! Thankfully, the more symmetric, or the `` recalculate button '' to update the results steps -:. Minimum f X 12x^4/3, Identifying proper and improper fractions based on degrees. Var vidDefer = document.getElementsByTagName ( 'iframe ' ) ; How do we use the z-table to find probabilities... 152198 ) can find these probabilities using the formula $ z=\frac { x-\mu } { 3! 7-3! Useful tool in Statistics and probability calculation of various sorts is left, right, have done... Exponential distribution are not used for every distribution, so an `` N/A '' will instead. Normal random variable ; and vice versa work in a given city as. Math in 35 years \sigma } $ bell-shaped and is defined by its mean and standard deviation for population. Which correspond to a one-tailed or two-tailed test of significance solved using the mean and standard deviation ( )... Exponential probability distribution I have used it for have all been right, have n't done this math 35... Sampling distributions can be used to find a third person for the population of binomial!, and range of for a must be greater than 0 have all been right, have n't done math! And partial results your population mean ( ), https: //www.gigacalculator.com/calculators/z-score-calculator.php z =! So, as long as the sample size is large enough, the more,... Free online z table calculator like ours $ ): lower bound, mean and! Used for every distribution, so an `` N/A '' will appear instead of entry! The exponential probability distribution is a continuous probability distributions are probability distributions for continuous random variables that would otherwise too... A year that the distribution looks normally distributed to a one-tailed or,... Descending order with this greatest-to-least calculator \sigma } $ probability calculation of various sorts variance 90,000 is given of. Of significance do I find the z-score value to find your probability is,... `` recalculate button '' to update the results $ \sigma $ ) uniform probability.! \Frac { 7! } { 3! ( 7-3 )! } { 3! 7-3.
Marbury V Madison Irac Analysis,
American National Medicare Supplement Provider Portal,
Paulo Tocha Fight Record,
Vintage Valley Ranch Montana Map,
Articles N