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# Normal distribution Excel

### NORMDIST function - Office Suppor

• A normal distribution graph in excel is a continuous probability function. It is a common method to find the distribution of data. A formula has been found in excel to find a normal distribution which is categorized under statistical functions. This is completely depending on the mean and standard deviation
• The equation for the normal density function (cumulative = FALSE) is: When cumulative = TRUE, the formula is the integral from negative infinity to x of the given formula. Example. Copy the example data in the following table, and paste it in cell A1 of a new Excel worksheet. For formulas to show results, select them, press F2, and then press Enter
• Normdist function in Excel is under the statistical category, which is used to calculate the Normal Distribution of any data on the basis of Mean and Standard Deviation. Normal Distribution shows how the data points are distributed and the means and shows the standard deviation in both sides of the mean
• In Excel, the NORM.INV function returns a normally distributed value given a probability, a mean, and a standard deviation. NORM refers to a normal distribution with a given mean and a given standard deviation. and INV refers to inverse, that is, finding a value given a probability, rather than finding a probability given a value.

To generate a normal distribution in Excel, you can use the following formula: =NORMINV (RAND (), MEAN, STANDARD_DEVIATION) You can then copy this formula down to as many cells in Excel as you'd like, depending on how large you'd like the dataset to be The NORM.S.DIST Function is categorized under Excel Statistical functions. It will calculate the Excel Standard Normal Distribution function for a given value. The NORM.S.DIST function can be used to determine the probability that a random variable that is standard normally distributed would be less than 0. It has three basic factors to calculate the normal distribution in excel: X: X is the specified value for which we want to calculate normal distribution. Mean: Mean is whereas average of the data. Standard_Dev: Standard Deviation is a function to find the deviation of the data. (It has to be a. To create a normally distributed set of random numbers in Excel, we'll use the NORMINV formula. The NORMINV formula is what is capable of providing us a random set of numbers in a normally distributed fashion. The syntax for the formula is below: = NORMINV ( Probability, Mean, Standard Deviation) The key to creating a random normal distribution is nesting the RAND formula inside of the NORMINV formula for the probability inpu The Excel NORM.DIST function returns values for the normal probability density function (PDF) and the normal cumulative distribution function (CDF). The PDF returns values of points on the curve. The CDF returns the area under the curve to the left of a value Excel can calculate CDF with the formula: =NORDIST(x value, Sample Mean, Sample Standard Deviation, TRUE) Set up the tables for calculating the CDF of each bin by copying the bin designations onto the descriptive statistics worksheet that Excel previously created for you and creating two columns, one for total CDF and one for bin CDF The formula NORMINV () function in excel basically generates a number that has a probability represented by RAND () and which belongs to a normal distribution curve with a mean represented by mean_value and standard deviation represented by standard_deviation in the above formula Define the bands for distribution Assuming the test scores range from 0 to 100, you can define score bands like 10,20,30,40,50,60,70,80,90,100 2. Create a frequency formula and array enter it in to the spreadshee How To Sample The Normal Distribution In Excel (Normal Distribution In Excel Part 2) - YouTube. Watch later. Share. Copy link. Info. Shopping. Tap to unmute. www.grammarly.com. If playback doesn't. e.g. NORMSDIST for the standard normal distribution e.g. NORMDIST for the normal distribution ; A value of x such that Pr(X <= x) = p for some specified value of p is called the inverse of the cumulative distribution function. So the Excel command includes INV e.g. TINV for the T distribution e.g. NORMSINV for the standard normal distribution FREE EXCEL TIPS EBOOK - Click here to get your copy A bell curve (also known as normal distribution curve) is a way to plot and analyze data that looks like a bell curve. In the bell curve, the highest point is the one that has the highest probability of occurring, and the probability of occurrences goes down on either side of the curve Normal Distribution in Excel (NORMDIST) NORMDIST or normal distribution is an inbuilt statistical function of Excel that calculates the normal distribution of a data set for which the mean and standard deviation are given. NORMDIST function accepts four arguments-X value, mean, standard deviation, and cumulative value

It's a well known property of the normal distribution that 99.7% of the area under the normal probability density curve falls within 3 standard deviations from the mean. So to graph this function in Excel we'll need a series of x values covering (μ-3σ,μ+3σ). This is the probability density function for the normal distribution in Excel Contents. normal distribution excel template worksheets provides your Excel worksheet much more flexibility. In order to make use of Excel worksheets to do the job that you want, it is essential to know how to make use of the formulas and also data that are had in the template. If you recognize the formula, after that you will not have troubles The normal distribution that we are trying to fit data has as its two and only parameters the sample's mean and standard deviation. The CDF of this normal distribution at any point on the x-Axis can be determined by the following Excel formula: CDF = NORMDIST ( x Value, Sample Mean, Sample Standard Deviation, TRUE The NORMDIST function is categorized under Excel Statistical functions. It will return the normal distribution for a stated mean and standard distribution. That is, it will calculate the normal probability density function or the cumulative normal distribution function for a given set of parameters Renvoie la distribution normale pour la moyenne et l'écart type spécifiés. Cette fonction a de nombreuses applications en statistique, y compris dans les tests d'hypothèse. Important : Cette fonction a été remplacée par une ou plusieurs nouvelles fonctions proposant une meilleure précision et dont les noms reflètent mieux leur rôle

### Normal Distribution Formula in Excel How to Use

1. How to use the NORMDIST function to calculate the probability for normal distributions
2. Now for each of those points the normal distribution shall be calculated using Excel's NORMDIST function. The first parameter is the values we calculated, the second the mean, the third the standard deviation and the last should be FALSE as we don't want cumulative (NORMDIST(Q1,100.84,27.49,FALSE))
3. An Introduction to Excel's Normal Distribution Functions Excel provides several worksheet functions for working with normal distributions or 'bell-shaped curves.' This introduction to Excel's Normal Distribution functions offers help for the statistically challenged
4. normal distribution curve excel template worksheets gives your Excel worksheet a lot more versatility. In order to utilize Excel worksheets to do the work that you desire, it is required to understand just how to use the formulas as well as information that are included in the template

Excel Normal Distribution You can experiment with it and add new information. Also you can check how the graph changes by changing the standard deviation: for lower values of standard deviation, you will notice that the chart gets more centered around the mean and the opposite happens for higher values of standard deviation Normal distributions have key characteristics that are easy to spot in graphs: The mean, median and mode are exactly the same. The distribution is symmetric about the mean—half the values fall below the mean and half above the mean. The distribution can be described by two values:. Excel Basics — Finding areas under the normal distribution. Excel has some very useful functions for finding areas under the normal distribution. NORMSDIST(z) Z is the value for which you want the distribution. Returns the standard normal cumulative distribution function. The distribution has a mean of 0 (zero) and a standard deviation of one Enter =NORMDIST(a1,0,1,0) into cell B1. This tells Excel to calculate the standard normal distribution from the value you entered in cell A1 with a mean of 0 and a standard deviation of 1. Press enter. Using the same motion you used in Step 1, drag the fill handle from the corner of cell B1 down to cell B33

### How to Create a Normal Distribution with Excel: 8 Step

1. In our previous post, we have discussed what is normal distribution and how to visually identify the normal distribution.However, deeper analysis is require to validate the normality of the data since it is affecting our analysis method. Most us are relying to our advance statistical software such as Minitab, SigmaXL, JMP and many more to validate the data normality
2. I want to know how to check a data set for normality in Excel, just to verify that the requirements for using a t-test are being met.. For the right tail, is it appropriate to just calculate a mean and standard deviation, add 1, 2 & 3 standard deviations from the mean to create a range then compare that to the normal 68/95/99.7 for the standard normal distribution after using the norm.dist.
3. Normal Distribution. The normal distribution is one of the most important distributions in statistics. In this part of the website, we will explore the following topics about this distribution, although additional information about this distribution will be provided throughout the website. Topics: Basic Characteristics
4. g almost any kind of statistical analysis. Today we will learn how you can make a statistical distribution of test scores using excel. There is a downloadable workbook too, for you to take a look at the formulas and play with them

### How to Generate a Normal Distribution in Excel - Statolog

(This is the first of two articles about normal distributions. The second article is, How to Create Monte Carlo Models and Forecasts Using Excel Data Tables. Back when I created models and forecasts for employers, I KNEW that my results were going to be wrong, and I had no practical way to express any degree of uncertainty in my results Excel Functions: Excel provides the following two functions: LOGNORM.DIST(x, μ, σ, cum) = the log-normal cumulative distribution function with mean μ and standard deviation σ at x if cum = TRUE and the probability density function of the log-normal distribution if cum = FALSE. These functions are not available in versions of Excel prior to.

### NORM.S.DIST Function - Excel Standard Normal Distributio

The distributions above were generated using Excel's NORMSDIST function using an average of 100, one of the three standard deviations above and an X values range from 20 to 180. So, if you know your process average and process standard deviation, you can easily draw the normal distribution for your process Standard Normal Distribution The Bell Curve with a mean of 0 and standard deviation of 1. The curve is symmetric around 0 Often called the Z distribution Z represents the number of standard deviations an observations is from the mean The most referenced distribution in statistics Using Excel's Norm.s.dist Functio

This article will show you exactly how to use the Normal Distribution in Excel to calculate the probability that your daily sales will fall below a certain limit. The advantages of statistics in Excel to solve business statistics problems is that most problems can be solved in just one or two steps and there is no more need to look anything up. The Excel NORM.INV function returns the inverse of the normal cumulative distribution for the specified mean and standard deviation. Given the probability of an event occurring below a threshold value, the function returns the threshold value associated with the probability Excel uses a slightly different algorithm to calculate percentiles and quartiles than you find in most statistics books. If you're interested, download the Excel file. 2. Use the PERCENTILE function shown below to calculate the 90th percentile. Excel returns the value 61.7. This means that 90% (18 out of 20) of the scores are lower or equal to. The first Excel function that we will examine is the NORM.S.DIST function. This function returns the standard normal distribution. There are two arguments required for the function: z and cumulative.. The first argument of z is the number of standard deviations away from the mean. So, z = -1.5 is one and a half standard deviations. Excel in T-SQL Part 2 - The Normal Distribution (NORM.DIST) Density Functions. Today's blog will be the second in a multi-part series on replicating Excel functions in T-SQL, continuing with.

Truncated Normal Distribution. Definition 1: Let -∞ ≤ a < b ≤ ∞. Then the pdf of the truncated normal distribution with mean μ and variance σ2 constrained by is. where φ is the pdf of the normal distribution and Φ is the cdf of the normal distribution. We assume that if x < a or x = -∞ then φ ( x, µ, σ) = 0 and Φ ( x, µ, σ) = 0 Since you want the normal distribution, the inverse of the cumulative normal distribution function is the function that you need to plug in your numbers into in order to get a random, normally-distributed range of values. This function in Excel is called NORM.S.INV(

Section 7.6 The Normal Distribution: An extended numeric example. Link to worksheets used in this section. We want to look at an extended example where we realistically want to find a definite integral, but need to use numerical methods rather than solving for the antiderivative and using the fundamental theorem of calculus Excel. The normal distribution's CDF (Cumulative Distribution Function) equals the probability that sampled point from a normal-distributed population has a value UP TO X given the population's mean, µ, and standard deviation, σ. The normal distribution's CDF is expressed as F(X,µ,σ)

### How to Create a Normally Distributed Set of - MBA Exce

The Normal Curve. The normal curve data is shown below. C1 and C2 have the normal distribution mean and standard deviation. Column E has the values for which we'll plot the normal distribution (from -380 in cell E3 to 380 in cell E41), and column F has the calculated distribution values For instance, consider the normal distribution with mean 50 and standard deviation 5. Below is a worksheet in which the area to the right of 60 is found. LAB ACTIVITIES FOR NORMAL DISTRIBUTIONS 1. (a) Use Excel to sketch a graph of the standard normal distribution with a mean of 0 and a standard deviation of 1 1 Answer1. Adelchi Azzalini has a page on how to generate pseudo-random numbers with skew-normal (SN) distribution. Here from the page: The N (0,1) variates u0 and v in step 1. can be calculated in Excel as NORMINV (RAND (),0,1). And δ expressed in terms of shape parameter α is δ = α/SQRT (1+α*α) Normal distribution is a bell-shaped curve where mean=mode=median. If you plot the probability distribution curve using its computed probability density function then the area under the curve for. Create a Normal Distribution Chart (Bell Curve) in Excel: In this article, we are going to learn how to Create a Normal Distribution Chart (Bell Chart) in b365 using Kutools.. You can create a Normal Distribution Chart in Excel for analyzing the probability of the events The data distribution that you are most likely to use during your analysis is the normal distribution to describe the different ways that you can work with a normal curve in Excel

### How to use the Excel NORM

1. g that a normal distribution curve is the right fit for all your data modeling
2. Select the data points and normal distribution values, then insert an X-Y Scatter chart. Use the Scattered with Smooth Lines version to create a bell curve in Excel. The chart may seem a bit off first. Let's see how you can make it look better
3. MATH 225N MATH Week 5 Assignment: Applications of the Normal Distribution - Excel.Question Sugar canes have lengths X that are normally distributed with mean 365.45 centimeters and standard deviation 4.9 centimeters. What is the probability of the length of a randomly selected cane being between 360 and 370 centimeters? • Round your answer to four decimal places
4. Normal distribution excel exercise. Video transcript. the normal distribution is arguably the most important concept in statistics everything we do or almost everything we do in inferential statistics which is essentially making inferences based on data points is to some degree based on the normal distribution so what I want to do in this video.
5. De normale verdeling of gaussverdeling (genoemd naar de Duitse wiskundige Carl Friedrich Gauss) is een continue kansverdeling met twee parameters, de verwachtingswaarde en de standaardafwijking, waarvan de kansdichtheid wordt gegeven door de volgende Gaussische functie: = ()De kansdichtheid is symmetrisch rond , hoog in het midden, en wordt naar lage en hoge waarden steeds kleiner zonder ooit.
6. The normal distribution has values below zero - clearly not the case for waiting time. No matter how quickly you greet customers, the time will not be a negative number. The tail of the normal distribution approaches zero at time a little less than 6 implying there are no values about that. There are some points (2 to be precise) above the USL
7. If mean = 0 and standard_dev = 1, NormInv uses the standard normal distribution (see NormSInv). Given a value for probability, NormInv seeks that value x such that NORMDIST(x, mean, standard_dev, TRUE) = probability. Thus, precision of NormInv depends on precision of NormDist. NormInv uses an iterative search technique

Hi Guys, I have been trying to create a bell curve / normal distribution chart but my data does not give a belle curve. What do I do wrong ? Given X values, I use formula z= STANDARDIZE Fx = NORM.DIST X z f(x) 490 0.9 0.029 490 0.9 0.029 490 0.9 0.029 474 -0.8 0.030 474 -0.8.. normal distribution. volume_up. normale verdeling {de} Voorbeeldzinnen. Voorbeeldzinnen voor normal distribution in het Nederlands. Deze zinnen komen van externe bronnen en zijn misschien niet nauwkeurig. Bab.la is niet verantwoordelijk voor deze inhoud Grafik distribusi normal atau kurva lonceng (Bell Curve) adalah distribusi yang sering muncul dalam berbagai situasi. Misalkan hasil nilai suatu mata pelajar.. In probability theory and statistics, the Poisson binomial distribution is the discrete probability distribution of a sum of independent Bernoulli trials that are not necessarily identically distributed. The concept is named after Siméon Denis Poisson.. In other words, it is the probability distribution of the number of successes in a collection of n independent yes/no experiments with. Standard Normal distribution - Excel Template. Home • Templates and Models • Standard Normal distribution - Excel Template. The normal distribution is the most widely used type of distribution in the world of finance. A number of models, statistical tools, and pricing methods rely on it

In Excel wordt de klokcurvegrafiek, ook wel normale distributiediagram genoemd, gebruikt om de waarschijnlijkheid van elke gebeurtenis te analyseren. Normaal gesproken kunt u het gemiddelde, de standaarddeviatie en de normale verdeling berekenen met behulp van formules en vervolgens de klokcurve-grafiek maken op basis van de berekende gegevens If mean = 0, standard_dev = 1, and cumulative = TRUE, NormDist returns the standard normal distribution, NormSDist. The equation for the normal density function (cumulative = FALSE) is: When cumulative = TRUE, the formula is the integral from negative infinity to x of the given formula. Support and feedbac The Excel NORM.INV function calculates the inverse of the Cumulative Normal Distribution Function for a supplied value of x, and a supplied distribution mean & standard deviation. The Norm.Inv function is new in Excel 2010 and so is not available in earlier versions of Excel. However, the function is simply an updated version of the Norminv. Normality tests check if a population significantly differs from a normal distribution. Available in Excel with the XLSTAT add-on statistical software. What are normality tests. Assuming a sample is normally distributed is common in statistics. But checking that this is actually true is often neglected Shading under a distribution curve (eg. normal curve) in excel We discussed on creating normal distribution curve in previous blog post. Please follow the same steps to create curve. Here we need some more calculations to find the truncation point to shade the curve. Let's say we want to have 50% (shaded) and 25% clear in both left and right

### Normality Test Using Microsoft Excel : Intact Prolink Blo

1. Normal Distribution Graph in Excel. Normal distribution graph in excel is a continuous probability function. It is a common method to find the distribution of data. A formula has been found in excel to find a normal distribution which is categorized under statistical functions. This is completely depending on the mean and standard deviation
2. Normal distribution is a means to an end, not the end itself. Normally distributed data is needed to use a number of statistical tools, such as individuals control charts, C p /C pk analysis, t-tests and the analysis of variance
3. While the normal distribution can often be useful for describing population distributions, it can also be very useful when working with sampling distributions. The sampling distribution of the sample mean can be estimated by a normal distribution and this works regardless of the shape of the population
4. Plotting Normal Distribution using Excel. 1. How do I convert non-normal distribution to a normal distribution? 0. Cumulative distribution function . Hot Network Questions What container for olive oil for longest shelf life
5. The Normal distribution requires two parameters, the mean and the standard deviation. A Normal distribution with a mean of zero and a standard deviation of 1 is also known as the Standard Normal Distribution (m =0, s =1) as in Figure 1. Figure 1 - Standard Normal Distribution. In Excel, there are multiple ways to draw this function
6. Normal Distribution in Excel. Loading... Exploring and Producing Data for Business Decision Making. University of Illinois at Urbana-Champaign 4.8 (894 ratings) Specifically, you will learn how to summarize data and learn concepts of frequency, normal distribution, statistical studies, sampling, and confidence intervals
7. In reality, even data sampled from a normal distribution, such as the example QQ plot below, can exhibit some deviation from the line. Frequency distribution You may also visually check normality by plotting a frequency distribution , also called a histogram, of the data and visually comparing it to a normal distribution (overlaid in red)

Step 5: Getting the Grouped Pivot Table. In the Grouping dialog box, you see the Starting at value is 27 as 27 is the lowest value of the score field. I want to make a frequency distribution as 21-30, 31-40, 41-50, and so on. So I enter 21 as the Starting at value. Suggested Ending at value is 100 The normal distribution curve is also referred to as the Gaussian Distribution (Gaussion Curve) or bell-shaped curve. Manufacturing processes and natural occurrences frequently create this type of distribution, a unimodal bell curve. A normal distribution exhibits the following:. 68.3% of the population is contained within 1 standard deviation from the mean A normal probability plot is an excellent way to compare an empirical distribution to a normal distribution. Its merits are that it clearly displays the nature of any deviations from normality: ideally, the points lie along the diagonal; vertical deviations from the diagonal depict deviations from normality. Its disadvantages are that many people do not know how to read it, so beware Alternately, the distribution may be exponential, but may look normal if the observations are transformed by taking the natural logarithm of the values. Data with this distribution is called log-normal. To make this concrete, below is an example of a sample of Gaussian numbers transformed to have an exponential distribution If mean = 0 and standard_dev = 1, NormInv uses the standard normal distribution (see NormSInv). Given a value for probability, NormInv seeks that value x such that NORMDIST(x, mean, standard_dev, TRUE) = probability. Thus, precision of NormInv depends on precision of NormDist. NormInv uses an iterative search technique

Did you know that you can use pivot tables to easily create a frequency distribution in Excel? You can also use the Analysis Toolpak to create a histogram. Remember, our data set consists of 213 records and 6 fields. Order ID, Product, Category, Amount, Date and Country Normal Distribution. Microsoft Access / VBA Forums on Bytes. Hi, What is the Access function for the Normal Distribution? (It is NORMDIST in Excel For the t-distribution, it is assumed that the standard deviation is 1 and mean is 0, whereas for the normal distribution functions, it is possible to specify these, or else in more recent versions of Excel that alternatively use the .S. in the middle of the expression Even if you are not in the field of statistics, you must have come across the term Normal Distribution. A probability distribution is a statistical function that describes the likelihood of obtaining the possible values that a random variable can take. By this, we mean the range of values that a parameter can take when we randomly pick up values from it Normal distributions become more apparent (i.e. perfect) the finer the level of measurement and the larger the sample from a population. You can also calculate coefficients which tell us about the size of the distribution tails in relation to the bump in the middle of the bell curve

### How to generate a sample set with normal distribution in Exce

• A theoretical distribution that has the stated characteristics and can be used to approximate many empirical distributions was devised more than two hundred years ago. It is called the normal probability distribution, or the normal distribution. It is sometimes called the Gaussian distribution
• Skewed Normal Distribution for Monte Carlo Simulations. I'm attempting to build a Monte Carlo simulation that simulates the potential prices for airline tickets. The model I've designed uses the Norm.Inv function where the mean is the average ticket price, the standard deviation is just an assumption of the spread, and the probability is RAND ()
• Normal Distribution Overview. The normal distribution, sometimes called the Gaussian distribution, is a two-parameter family of curves. The usual justification for using the normal distribution for modeling is the Central Limit theorem, which states (roughly) that the sum of independent samples from any distribution with finite mean and variance converges to the normal distribution as the.
• Random number distribution that produces floating-point values according to a normal distribution, which is described by the following probability density function: This distribution produces random numbers around the distribution mean (μ) with a specific standard deviation (σ). The normal distribution is a common distribution used for many kind of processes, since it is the distribution.
• You can also use the Random Number Generation tool in Excel's Analysis ToolPak Add-In to kick out a bunch of static random numbers for a few distributions. However, in this example we are going to make use of Excel's RAND() formula so that every time the worksheet recalculates, a new random number is generated.. Let's say we want to run n=5000 evaluations of our model

### Statistical Distributions in Excel - How to calculate

• When you're working with small samples in Excel — less than 30 or 40 items — you can use what's called a student t-value to calculate probabilities rather than the usual z-value, which is what you work with in the case of normal distributions. Excel provides six t-distribution functions. T.DIST: Left-tail Student t-distribution The T.DIST [
• The normal distribution is continuous probability distribution for real values random variables whose distributions are not known.. It is one of the important distribution in statistics. Normal distribution is mostly used in social sciences or natural. Normal distribution also known as Gaussian distribution.. A normal distribution is informally called as bell curve
• Key Terms . o Normal distribution. o Gauss distribution. o Bell curve. o Standardization. o Z-score. o Standard score. Objectives . o Recognize the normal distribution and its fundamental characteristics. o Know how to standardize a random variable using the Z-score. o Calculate probabilities for normally distributed dat

Normal Distribution in Statistics. By Jim Frost 165 Comments. The normal distribution is the most important probability distribution in statistics because it fits many natural phenomena. For example, heights, blood pressure, measurement error, and IQ scores follow the normal distribution. It is also known as the Gaussian distribution and the. The Excel NORM.S.INV function is a Statistical formula that calculates and returns the inverse of the standard normal cumulative distribution with a given probability. Frequently used in statistics and data analysis, the standard normal distribution is a normal distribution with a mean of zero (0), and a standard deviation of one (1)

### How To Sample The Normal Distribution In Excel (Normal

Normal distributions and non-normal distributions do a normal-quantile quantile plot as Jospeph prepared in Excel is considerably better than a histogram to check the distribution of. The standard normal distribution has a mean of zero and a standard deviation of one. The probability density vs standard deviations curve for the standard normal cumulative distribution is given below. NORM.S.INV Function in Excel. NORM.S.INV function returns the inverse of the standard normal cumulative distribution for the dataset With Excel Pivot Tables you can do a lot of stuff with your data! But did you know that you can even create a Frequency Distribution Table?. Let's have some fun below! I'll show you how easy it is to create your own Frequency Distribution Chart In Excel, il grafico della curva a campana, noto anche come grafico di distribuzione normale, viene utilizzato per analizzare la probabilità di ciascun evento. Normalmente, è possibile calcolare la media, la deviazione standard e la distribuzione normale utilizzando le formule, quindi creare il grafico della curva a campana in base ai dati calcolati

### EXCEL: Probability Distribution

Normal Distribution - General Formula. The general formula for the normal distribution is. f ( x) = 1 σ 2 π ⋅ e ( x − μ) 2 − 2 σ 2. where. σ (sigma) is a population standard deviation; μ (mu) is a population mean; x is a value or test statistic; e is a mathematical constant of roughly 2.72 Normal Distribution . The important thing to note about a normal distribution is that the curve is concentrated in the center and decreases on either side. This is significant in that the data has less of a tendency to produce unusually extreme values, called outliers, as compared to other distributions 