In order to measure customer sentiment about mall handicapped access, Stephanie the stats intern developed a post card mailer sent out to addresses in the local community that were randomly selected by a computer software program. Recipients were asked to respond online and were rewardedwith a mall coupon for doing so.

Which statistical sampling technique best describes her methodology?

1. cluster sampling
2. convenience sampling
3. judgment sampling
4. network sampling
5. quota sampling
6. simple random sample
7. snowball sampling
8. stratified sampling
9. systematic sampling