# 6.5 Normal distribution: summary of formulas

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Formula

## Normal probability distribution

$X$ ~ $N\left(\mu ,\sigma \right)$

$\mu$ = the mean $\phantom{\rule{20pt}{0ex}}\sigma$ = the standard deviation

Formula

## Standard normal probability distribution

$Z$ ~ $N\left(0,1\right)$

$z$ = a standardized value (z-score)

mean = 0 $\phantom{\rule{20pt}{0ex}}$ standard deviation = 1

Formula

## Finding the kth percentile

To find the kth percentile when the z-score is known: $k=\mu +\left(z\right)\sigma$

Formula

## Z-score

$z=\frac{x-\mu }{\sigma }$

Formula

## Finding the area to the left

The area to the left: $(P\left(X, x\right))$

Formula

## Finding the area to the right

The area to the right: $(P\left(X, x\right))=1-(P\left(X, x\right))$

## Normal distribution

• A continuous Random Variable (RV) with Probability Density Function (PDF) $f\left(x\right)=\frac{1}{\sigma \cdot \sqrt{2\cdot \pi }}\cdot {e}^{-\frac{1}{2}\cdot {\left(\frac{x-\mu }{\sigma }\right)}^{2}}$ , where μ is the mean of the distribution and σ is the standard deviation.
• Notation: X ~ N(μ, σ). If μ=0 and σ=1, the RV is called the standard normal distribution.

## Standard normal distribution

• A continuous random variable (RV) X~N(0,1). When X follows the standard normal distribution, it is often noted asZ~N(0,1).

## Z-score

• The linear transformation of the form $z=\frac{x-\mu }{\sigma }$ . If this transformation is applied to any normal distribution X~N(μ,σ), the result is the standard normal distribution Z~N(0,1). If this transformation is applied to any specific value x of the RV with mean μ and standard deviation σ , the result is called the z-score of x. Z-scores allow us to compare data that are normally distributed but scaled differently

#### Questions & Answers

what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
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