A normal distribution is a symmetrical distribution. In a normal distribution mean, mode and median of the data set are equal. All values are cluster around the mean or average in a normal distribution. The normal curve is a bell shaped and the total area under the curve is equal to one. Normal distribution is based on two parameters that are mean and variance.

Z= [x- mean]/ standard deviation

For each value of x we get different values of z. These values are checked in area table to find the value of area under the curve.

Z= [x- mean]/ standard deviation

For each value of x we get different values of z. These values are checked in area table to find the value of area under the curve.