Two Proportion z-Intervals
A biologist wants to compare the proportions of rainbow trout infected with whirling disease (an illness of trout and salmon caused by a microscopic parasite) coming from two separate watersheds. For each watershed, the biologist will collect a random sample of trout and record the proportion infected in the sample. The biologist intends to estimate the difference for all trout in the two watersheds. Assuming all conditions for inference are met, which of the following is the most appropriate method for the biologist to use to analyze the results?
A two-sample z -interval for a difference in sample proportions
A two-sample z -interval for a difference in population proportions
A one-sample z -interval for a population proportion
A one-sample z -interval for a difference in sample proportions
A one-sample z -interval for a sample proportion