Which statement best completes this diagram?

Arecent poll of 500 residents in a large town found that only 36% were in favor of a proposed referendum to build a new high school. find the margin of error for this poll if we want 95% confidence in our estimate of the percentage of residents in favor of this proposed referendum.

Which factor contributed to the rise of african empires such as ghana and mali ? a. their creation and involvement in trade networks b. they focused only on agricultural production. c. they didn’t engage in warfare with other nations d. their geographic location protected them from attacks.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.