A travel agency surveys 100 adults in the local area regarding their travel habits. Among the findings, the travel agency discovers that 90 percent of survey participants indicate that they are willing to travel between 100 and 200 miles to attend a family reunion. However, beyond a distance of 200 miles, the percentage of survey participants willing to travel to a family reunion plummets to under 30 percent. Within this context, 200 miles represents a(n)