Many delivery trucks feature a "How Am I Driving?" sticker on the rear bumper, along with a phone number. This sticker allows drivers to report erratic driving by the truck driver or offer a compliment if they like. A dispatcher at the
trucking station accepts calls and records information from those who call the phone number. The dispatcher reports
that in the past month, 218 calls were received. Of those calls, 178 reported negative driving behaviors by the truck
drivers. How might this data-collection method produce bias in obtaining an estimate of all drivers who are satisfied
with the company's truck drivers?