Describe a survey sample and a survey question that would be likely to lead to valid results. A teacher wants to know whether his students prefer to have a class party at an ice-skating rink or at an amusement park.
​

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?