The rated life of a bearing varies

Not sure please explain

I think this question is for ball bearing
For roller bearing the power to be 1/3

For ball bearing: p=3
For roller bearing: p=10/3
p is the exponent of life equation:
L=(C/P)^p

This is for ball bearing only.. for roller bearing it is 1/3

L=(C/P)^3
L=rated life
P=equivalent radial load
C=dynamic load capacity
So load varies inversely as cube of load

L10= (C/P)^p
Where, L10 - Basic Rating Life
P- Load
C- Load Rating
p- for ball bearing 3
- for Roller bearing 3.3333.

L= (C/p)^3

The total number of revolutions before a failure occurs is called the basic rating life. The bearing life of individual bearings varies considerably, even if they are of the same size, same material, same heat treatment and are under the same operating conditions.

Plz any one of you explain it