A recent study by Dommeyer (2008) examined what factors influence whether or not people respond to a mail survey. In other words, are there factors that can influence if a person responds to a survey that he or she received in the mail? Dommeyer wanted to know if the attractiveness of the researcher (attractive and not attractive) in a cover letter would influence if people responded to the mail survey. Dommeyer also wanted to know if the sex of the researcher (male or female) in the cover letter would influence if people responded to the mail survey. The first independent variable was attractiveness of the researcher in the cover letter. This independent variable had _____ levels.