Part 1.

The z distribution can be used to find the percentile when a particular X is above the mean. To find the percentile, first find the z score corresponding to the given X. Next, find the area under the z distribution curve that corresponds to the z score. Finally, the percentile is the value that falls at or below the given area.
Z = (X-μ)/σ If you want to find the percentile for a particular X that is above the mean, you would use the following equation:

 P = (X-μ)/σ + 1/2 

For example, if you want to find the 95th percentile for a particular X that is above the mean, you would use the following equation

: P = (X-μ)/σ + 1/2 P = (X-μ)/σ + 1/2 P = 1.645

Part 2

The percentile is the value below which a certain percentage of the data falls. To find the percentile when a particular X value is below the mean, find the value below which the given percentage of the data falls and multiply it by the given percentage.

The z-distribution is used to find the percentile when a particular X value is below the mean. The z-distribution is a bell-shaped curve that is used to find the percentage of data that is located at a given point. The percentile is the value that is located at the given point. 
The z value can be found using the following equation: 
Z = (X - µ) / σ.

 Once the z value is found, the percentile can be found using the following equation: 
P = 1 - (Area to the left of z)