Answer:
Dependent: Number of Grievances
Independent: Plant
Step-by-step explanation:
Dependent variables are the variables that are caused by something else, they are dependent on another variable.
Independent variables are variables that the researcher can change and thus are the cause of an effect (the effect being recorded as the dependent variable). We often change these variables so we can compare them.
Thus the thing we are observing is the varying amount of grievances across the four plants. The complaints are dependent on the plant that they came from (we are assuming one plant treats workers poorly) and thus the number of complaints is dependent on which plant.