Calculate the 88th percentile for X.

Let X follows normal distribution with mean 0 and standard deviation 1.

The 88th percentile for X is,

$\begin{array}{rcl}P\left(X<x\right)& =& 0.88\\ P\left(\frac{X-\mu }{\sigma }<\frac{x-0}{1}\right)& =& 0.88\\ P\left(z<x\right)& =& 0.88\end{array}$

The probability 0.88 would be converted to z score can be obtained using the excel formula “=NORM.S.INV(0.88)”. The z score value is 1.1750.