A variable is an empirical measurement of a ________________.

Cell phones pose a threat to public opinion research because a. the majority of households with residents over age 65 do not use them. b. they do not accept toll-free calls from research firms. c. almost 40% of households no longer have landlines

d. most cell phone users won't answer a number they don't recognize.

The goal of the Paris climate accord is to keep the global average temperature from rising ______.

a. as much as 4° Celsius above pre-industrial levels b. as much as 4° Fahrenheit above pre-industrial levels c. as much as 2° Celsius above pre-industrial levels d. as much as 2° Fahrenheit above pre-industrial levels