Points and stuff for the people

What is the difference between regular convex and concave polygons

1) you deposit $2,500 in an account that earns 4% simple interest. how much do you earn in eight years?

For a science project, a high school research team conducted a survey of local air temperatures. based on the results of the survey, the found that the average temperatures were around 10 degrees higher than expected. this result was wrong. the trouble with the survey was that most of the locations were exposed to direct sunlight and located over asphalt or sand, which resulted in higher temperatures than normal. this is a classic example of an error in which phase of inferential statistics?