Final answer:
Dock workers are expected to demand higher pay due to the increased risks and challenging working conditions compared to grocery store cashiers.
Step-by-step explanation:
In this scenario, we can expect that dock workers will demand higher pay. This is because being a dock worker is more dangerous and requires workers to work odd hours compared to being a grocery store cashier. The equilibrium wage for grocery store cashiers is $15 per hour. Sam's Supermarket plans to pay dock workers the same wage of $15 per hour, but considering the added risks and challenging working conditions, dock workers will likely demand higher pay to compensate for the increased hazards and inconveniences.