A factory produces plastic parts used to fit in car dashboards. It is important that the parts are produced with the correct dimensions, or they may not fit in the car dashboard. To ensure that the parts are being made correctly, a sample of parts is checked and measured each day. Which of the following methods would not represent a convenience sample? Right after lunch, the first 25 parts are inspected.
Fifty parts are chosen at random from the many parts made each day.
At the end of the day, a container of 30 parts is inspected and measured.
The first 20 parts produced after the start of the day are inspected and measured.