Determine whether the study described is a randomized experiment or an observational study. A math department chair wants to determine the effectiveness of online homework systems. She selects four college algebra classes where each one is set up to use a different online homework system. Students have already enrolled in the classes. She administers a common pretest and final exam to measure the effectiveness.

observational study, she is in control of all of the variables.

Explanation:

answer; /// i do believe that the correct answer is (d) cooperative play; /// good luck

d.

thist title points out that you are explaining the nature of the u.s. government. it is the most specific. a representative government consists of a government where decisions are taken according to a voting system. the most essential aspect of a representative government is found in the different structures where voting rights are granted to different groups of people. for example, voting for governor, mayor, president, local police chief etc.