Do out-of-state motorist violate the speed limit more frequently than in-state motorists? This vital question was addressed by the highway patrol in a large eastern state. A random sample of the speeds of 2,500 randomly selected cars was categorized according to whether the car was registered in the state or in some other state and whether or not the car was violating the speed limit. The data follow.
In State Cars Out of State Cars
Speeding 521 328
Not Speeding 1141 510
Estimate with 95% confidence the difference in population proportions. Briefly describe what the interval estimate tells you.
This solution calculates the difference in population proportions by determining the upper and lower confidence level.