Question

Do out-of-state motorists violate the speed limit more frequently than in-state motorists? The highway patrol in some state wants to see if this true. A random sample of 2500 cars was classified according to whether the car was registered in the state or in some other state and whether or not the car was exceeding the speed limit. The data is in the table below:

                                   |      In State     Out of State

              Speeding            |      1590               324

              Not speeding        |         510               76

At the 5% significance level, what sample size would be needed to have a power = .95 if when (p₁-p₂) = 0.1

Answer 1