Question

A Human Factors Engineer developed predictions about automobile accidents at intersections based on the distance drivers had to turn their heads to check traffic. These predictions lead to the expectation that a 3:2:1 ratio would be found for 4-way intersections, Y-intersections, and 2-way intersections. The following figures were obtained from intersections with equal traffic flow. Test the engineer's theory. Total accidents = 200; please calculate the X² and write out your conclusions. Don't forget the specific interpretations.

The observed accidents are the following:

4 way = 116

Y = 60

2 way = 24

What is the critical value? Please show all work for credit, including the labeling of O and E.

tip: predicted accident at Y intersection is 66.67

Answer 1

Critical value is calculated using chi square table for 2degrees of freedom