A study is conducted to investigate whether customer satisfaction is greater among computer companies that offer tech support versus those that do not offer tech support. A random sample of 50 customers are selected from among those that purchased computers that offer tech support. A separate random sample of 40 customers are selected from among those that purchased computers that do not offer tech support. The study found that the mean satisfaction rating was significantly greater among customers that purchased computers that offer tech support. Which of the following is the best description of this study? A) An experiment using a completely randomized design.
B) An experiment using a randomized block design.
C) An experiment using a matched pairs design.
D) An observational study using a simple random sample.
E) An observational study using a stratified sample.