Help~ tmolo test i cant figuar out this

[skyliner34]

find the electric field 2.5m from the center of region of space with a charge density given by ro=5.5E-15 R**(2.3)

i flip all over the book, i still can't find anything to solve this question, can anyone help?
the ans from the back of the book is .00241

 

[miknsk]

AFAIR, it might be supposed that bulk charge within sphere is equal to the point charge
Q=(4/3)*Pi*(R^3)*ro placed into the center of sphere.