Which function is negative for the interval [–1, 1]?

An education expert is researching teaching methods and wishes to interview teachers from a particular school district. she randomly selects ten schools from the district and interviews all of the teachers at the selected schools. which type of sample did she use in this study? a)systematic sample b)probability sample c)stratified sample d)cluster sample

Potentially, a large spill can be: a) an environmental threat, if it gets into drains b) a dangerous fire hazard c) harmful to individuals d) all of the above

Which at first gave the south an edge in the civil war? a. a better-equipped army b. the invention of ironclad ships c. the drafting of slaves into the army