Azzera filtri
Azzera filtri

random variable with normal distribution

1 visualizzazione (ultimi 30 giorni)
Tony il 11 Nov 2013
Risposto: Roger Stafford il 11 Nov 2013
Hello, here is the problem:
A random variable obeys a normal distribution. It has a mean value equal to 100 and a standard deviation equal to 3. Find the probability that:
x < 98
98 < x < 104
x > 98
I have a slight idea i know how to find mean using mean(x) and randn(x) for some random number but no idea how to tie them together.
thank you for your time

Risposte (3)

Matt J
Matt J il 11 Nov 2013
See the erf() command.

Image Analyst
Image Analyst il 11 Nov 2013
If you want to do it empirically (like Monte Carlo), you can use this:
numberOfNumbers = 1000000; % Whatever number you want.
% From the help:
randomNumbers = 100 + 3 * randn(1, numberOfNumbers);
% Count number less than 98
count = sum(randomNumbers < 98)
fprintf('The number of numbers less than 98 = %g%%\n',...
count * 100 / numberOfNumbers);
Repeat for other ranges.

Roger Stafford
Roger Stafford il 11 Nov 2013
The Statistics Toolbox function 'normcdf' is just what you need.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by