An environmentalist wants to determine if the median amount of potassium (mg/L) in rainwater in Lincoln County, Nebraska, is different from that in the rainwater in Clarendon County, South Carolina. She randomly selects 22 weeks in the Nebraska location in which it rained at least once during the week and 20 weeks in the South Carolina location in which it rained at least once during the week and determines the potassium levels in the rainwater. Her data are shown in the following table:

Do the data indicate a difference in potassium levels at the α = 0.05 level of significance?