Question

Traffic accidents: Traffic engineers compared rates of traffic accidents at intersections with raised medians with rates at intersections with two-way left-turn lanes. They found that out of 4644 accidents at intersections with raised medians, 2272 were rear-end accidents, and out of 4587 accidents at two-way left-turn lanes, 2000 were rear-end accidents.

Part 1 of 2

(a) Assuming these to be random samples of accidents from the two types of intersection, construct a 99% confidence for the difference between the proportions of accidents that are of the rear-end type at the two types of intersection. Use the TI-84 calculator and round the answers to three decimal places. Let p1 represent the population for accidents at intersections with raised medians.

A 99% confidence interval for the difference between the proportions of accidents that are of the rear-end type at the two types of intersection is

<p1-p2<

Answer 1

Solution:-

We have,

C-Level:0.99

x1=2272, n1=4644, x2=2000, n2=4587

TI-84 calculator path: STAT > TESTS > B:2-PropZInt>enter require information > Calculate.

A 99% confidence interval for the difference between the proportions of accidents that are of the rear-end type at the two types of intersection is, 0.027<p1-p2<0.080