Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
0 votes

If $X$ a normal variate with mean $80$ and standard deviation $10$ compute the following probabilities by standardizing.$P(X\leq$80$)$

Can you answer this question?

1 Answer

0 votes
  • Standard normal distribution:
  • In a standard normal distribution $\mu=0,\sigma ^2=1$
  • The random variable $X$ can be converted to the standard normal variable $Z$ by the transformation
  • $Z=\large\frac{X-\mu}{\sigma}$
  • The probability density function $Z$ is $\phi(z)=\large\frac{1}{\sqrt{2\pi}}$$e^{-\Large\frac{1}{2}z^2};-\infty < Z < \infty$
  • $Z\sim N(0,1)$
Step 1:
$X\sim N(80,10^2)$
Let $Z=\large\frac{X-\mu}{\sigma}$
$\qquad=\large\frac{X-80}{10}$ be the standard normal variate.
Step 2:
$P(X\leq 80)$
When $X=80$
$\therefore P(X\leq 80)=P(Z\leq 0)$
answered Sep 19, 2013 by sreemathi.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App