The computer is expected to play an increasingly important role in crime control in the years to come. In 1983 the FBI had a non
computerized Ident system containing the records of thousands of persons across the country. A random sample of 500 records shows that only 70% of these records include information on the disposition of the case. This is unfortunate, since approximately 1/3 of all cases are eventually dismissed. If the dismissal is not part of the record, then an innocent person could be stigmatized. a) Assume that a new computerized criminal history system is developed and implemented. A random sample of size 500 is selected from the cases recorded in the new system. It is found that 410 of these include information on the disposition of the case. Estimate the proportion of cases in the new system that include information on the disposition of the case.
b) Estimate the difference in proportions between the old Ident system and the new computerized system. (Subtract in the order New-Ident)
c) Find a 95% confidence interval on the difference in proportions.
d) It is safe to say that the new system is superior to Ident in the sense that it contains more "disposition of case" information? Explain, based on the confidence interval of part (c).
