# normal-distribution's questions - English 1answer

3.384 normal-distribution questions.

### Comparing probabilities generated by two different normal cumulative approximations [on hold]

Suppose I have two ways of approximating cumulative normal probability and I want to compare whether the two methods are equivalent. The most obvious way to go about it would be to have a bunch of ...

### normality testing

1 answers, 176 views normal-distribution goodness-of-fit
What is the best method for testing for normality? I have a smaller data set today (30 in each group) and on the histograms none of them look normally distributed at all, whereas with the skewness ...

### How to correctly use the z-transformation in deriving the normal pdf from the binomial

I have understood that the Normal distribution may be motivated by considering the Binomial distribution for large N. I wished to create a geogebra file but encountered a problem I'd not thought of ...

### Acceptance rejection with Halton sequence as RNG

I am coding various normal random variable generators, one of them being the acceptance rejection method: ...

### 1 Help with computing message on TrueSkill factor graph

I want to better understand the step for calculating the message from the game factor $h_{g}$ down to the difference variable $d_g$ on the TrueSkill factor. Such message is shown in the Rasmussen's ...

### 2 Comparing two values in a normal distribution after cutting off the tail of the distribution

I'm doing a sports-related analysis about comparing regular-season performance versus playoff performance, in particular which teams tend to do better during the playoffs. Thus, I'm making a "regular ...

### 1 Estimator of (left-)censored normal distribution when mean>>std

Suppose there is a left-censored normal distribution, and we know there is a total of $m$ samples, for which we know $n$ of them. I am trying to estimate the mean and variance of the underlying normal ...

### 1 Does a time-series have to be stationary before you calculate a z score or t score?

It's been a long time since basic statistics. I have a financial time-series that exhibits exponential growth. Before I standardize, do I have to make the time-series stationary? Before I ...

### Parameter which would make a Gaussian Distribution 'equal to' or 'closely fit' another Gaussian Distribution

I have these two Gaussian distributions: fX1 ~ N (10, 12)12 is the variance and not standard deviation ...

### 3 Are all continuous random variables normally distributed?

All the time I see examples of the normal/Gaussian distribution with continuous random variables. So my question is do all continuous random variables have a Gaussian distribution?

### 1 Normality distribution? [on hold]

I try the shapiro.test for my transformed dataset (logarithm). I obtain p value 0,0001207. I try to draw the graph of distribution and obtain this graph (I attached). For you, do I have a normal ...

### -2 Calculating Variance for a Normal Distribution [closed]

I want to add noise to a given time series of data. The noise is to be generated using a distribution technique. For example for an interval of 10 min I have 60 entries which sum upto say 13643Kw. ...

### Conditional expectation of RVs under truncation-based stochastic signal release?

Suppose $z\sim N(0,1)$ and $x\sim N(\gamma z, 1)$, where $\gamma$ is a known sensitivity parameter. That is, $x=z+\epsilon, \epsilon \sim N(0,1)$ where $\epsilon$ is exogenous. Further, suppose there'...

### 2 What is the probability of at least one of a sum of normally distributed variables being greater than a threshold?

0 answers, 168 views normal-distribution quality-control
Let's say I have a pencil factory. I don't mind if my pencils are too short, but it's important they're not too long. My Quality Control department measure each pencil, and their measurement will be ...

### 2 Calculate standard deviation given mean and percentage

2 answers, 4.991 views normal-distribution standard-deviation
Some values have a normal distribution with mean .0276. What standard deviation is required so that 98% of values are between .0275 and .0278? What I'm confused with is how to calculate the standard ...

### 1 Bernoulli and normal distribution

I know that a sum of RVs bernoulli distributed with the same parameter $p$ may be approximated with a normal distribution. My question is whether a single bernoulli RV may be approximated with a ...

### 4 Can anyone tell me why we always use the Gaussian distribution in Machine learning?

For example, we always assumed that the data or signal error is a Gaussian distribution? why? I have asked this question on stackoverflow, the link: https://stackoverflow.com/questions/12616406/...

### for normal distribution, what is probability x>5y?

It should be a simple statistic question: X,Y ~ Phi(0,1) (normal distribution). What is the probability that X > 5*Y Anyone can teach me how to do it?

### 3 mean and variance of norm of normal random variables

If $x$ and $y$ are independent and normally distributed:$$x\sim N(\mu_x,\sigma_x)$$ $$y\sim N(\mu_y,\sigma_y)$$ and $r$ is a random variable with the following relationship to $x$ and $y$ r = \sqrt{...

### 2 Why don't I see my points on cullen and frey graph

I have a set of data of 5 members. based on some previous questions , I was expecting to see where my actual points are located on the graph. in my case I see the theoretical but not my points. just ...

### GLMMs, stable isotope distribution analysis

I am currently working with a set of samples of stable isotopic concentrations obtained from a group of individuals. I am trying to process this data through a glmm() from the package lme4 to ...

### 6 Binomial-logit-normal

I'm watching a pool match and at the start of the first game the person next to me says "I think the chance of player A winning the first game is $.700$. If he wins that I think the chance of him ...

### Training Gaussian Restricted Boltzmann Machines with Noisy Rectified (nrelu or ssu) linear hidden units

0 answers, 8 views normal-distribution train rbm
I'm not sure how to implement this architecture. I'm following this thesis http://www.cs.toronto.edu/~ndjaitly/Jaitly_Navdeep_201411_PhD_thesis.pdf (pag 17-19) or this paper http://www.cs.toronto.edu/~...

### 2 A question about Histogram-to-distribution transformation

I have done a simulation with 1 million runs on Matlab. I have got a histogram for this. Using Matlab command hist(X), (where X is the 1 million samples as results ...

### 2 Normal approximation to Poisson: With Continuity Correction the Approximation Seems Worse

This is Exercise 3 in Section 6.3 of Probability and Statistics, 4th edition, by DeGroot and Schervish: Suppose that the distribution of the number of defects on any given bolt of cloth is the ...

### 1 Why standard normal samples multiplied by sd are samples from a normal dist with that sd

This answer notes that if a programming language/libraries provide a procedure that returns random samples from a standard normal distribution, we can generate samples from another normal distribution ...

### Discrete version of multivariate normal distribution

Let's say that I have a 2d map, and I would like to explore around my house. Drawing samples from a bivariate gaussian centered at the x, y location of my house makes sense, as I don't want to stray ...

### Statistical time series analysis using Percentile and Empirical Rule

I analysing time-series to see the range of an asset. I have data for GBPUSD so i could only analyze this so far. I have used both empirical rule and percentile. Of course they give different ...