The table at the right shows how much tony earns per hour for his summer jobs one day tony spends 3 hours running errands he wants to use the money from his job to buy two banners.
table numbers
walking dogs $ 8
mowing lawns $10
running errands $6

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.

In the rectangle below ac=30 units what is de

Which situation is an example of an observational study?