This is the “bell-shaped” curve of the Standard Normal Distribution.

It is a Normal Distribution with mean 0 and standard deviation 1.

It shows you the percent of population:

between 0 and Z (option “0 to Z”)

less than Z (option “Up to Z”)

greater than Z (option “Z onwards”)

It only display values to 0.01%

## The Table

You can likewise utilize the table beneath. The table shows the territory from 0 to Z.

Rather than one LONG table, we have put the “0.1”s running down, at that point the “0.01”s running along. (Case of how to utilize is beneath)

Example: Percent of Population Between 0 and 0.45

Start at the row for 0.4, and read along until 0.45: there is the value 0.1736

And 0.1736 is 17.36%

So 17.36% of the population are between 0 and 0.45 Standard Deviations from the Mean.

Since the bend is balanced, a similar table can be utilized for values going either bearing, so a negative 0.45 additionally has a territory of 0.1736

Example: Percent of Population Z Between -1 and 2

From −1 to 0 is the same as from 0 to +1:

At the row for 1.0, first column 1.00, there is the value 0.3413

From 0 to +2 is:

At the row for 2.0, first column 2.00, there is the value 0.4772

Add the two to get the total between -1 and 2:

0.3413 + 0.4772 = 0.8185

And 0.8185 is 81.85%

So 81.85% of the population are between -1 and +2 Standard Deviations from the Mean.