Take the following as truth: If WTP for reductions in mortality risk is linear in risk reduction, then a WTP of $50 for a reduction of 1/100,000 implies a WTP of $500 for a risk reduction of 1/10,000 (which is ten times the risk reduction valued in the study).
Then the following statement: "The WTP for reducing mortality risk might be linear." is true, false, or inconclusive?