If X is a normal variable with a standard deviation of 2 and Pr(X<9) = 0.8 Find the mean. Im new to the whole normal distribution thing so i would really appreciate some help. thanks
Follow Math Help Forum on Facebook and Google+
Originally Posted by Kash If X is a normal variable with a standard deviation of 2 and Pr(X<9) = 0.8 Find the mean. Im new to the whole normal distribution thing so i would really appreciate some help. thanks Find the value z* of Z such that Pr(Z < z*) = 0.8. Substitute this value into $\displaystyle Z = \frac{X - \mu}{\sigma}$: $\displaystyle z* = \frac{9 - \mu}{2}$. Solve for $\displaystyle \mu$.
wow i didnt know that formula!, thanks alot!