The Virginia Department of Environmental Quality (VDEQ) Uses Probabilistic Monitoring

Multiple Choice

The Virginia Department of Environmental Quality (VDEQ) uses probabilistic monitoring to regulate the water quality of streams in the Commonwealth of Virginia. Of the 85 Eastern Virginia Sites (group 1) , 17 do not meet minimum requirements. Of the 80 units sampled in Western Virginia Sites (group 2) , 24 do not meet minimum requirements. Assume the data can be treated as independent simple random samples. What is the value of the z test statistic for testing the equality of the proportions of streams that fail to meet minimum requirements in the two areas?

A) z = -1.49
B) z = -1.65
C) z = -1.96
D) z = -2.33