Police stops, race, crime rates, arrest rates

[Bill Lear <rael@xxxxxxxxxx>]

Suppose we have 100 people, 90 white, 10 black, and the following stats:

5 blacks commit crime
4 are arrested
black arrest rate is 80% of black crimes, 40% of black population
"true" black crime rate is 50% of black population, 5% of total population
police search 50% of black motorists without cause

50 whites commit crime
20 are arrested
white arrest rate is 40% of white crimes, 22% of white population
"true", white crime rate is 55% of white population, 50% of total population
police search 10% of white motorists without cause

How do I find these numbers?  Is it possible to know the "true" crime
rate?  I'm assuming violent crimes, or perhaps "street" crimes.  Are
there figures that measure the above for street crimes, white collar
crimes, drug crimes?

How much of reported crime (I'm assuming arrest rates are the conventional
measure?) by blacks and whites is a result of differential attention
paid to these two groups by law enforcement?

How have laws changed to perhaps direct law enforcement to treat the
groups differently?


Bill