Apublic opinion poll in virginia wants to determine whether registered voters in the state approve of a measure to ban smoking in all indoor restaurants in the interest of public health. the researchers select a simple random sample of 5 counties and then sample all registered voters from each selected county and ask whether they approve or disapprove of the measure. this is an example of:
a. a simple random sample
b. a multistage sample
c. a stratified sample.
d. a cluster sample
e. a systematic sample

In some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. the production of sterile male ligers is an example of read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. the production of sterile male ligers is an example of a postzygotic barrier the founder effect sympatric speciation a prezygotic barrier

How do economists measure the success, or shortcomings, of the economy?

Why have the aztec ruins in mexico city not been dug up?