Which hypothesis describes the assumption that a dose–response curve derived from high dose-rate data may be extrapolated to low or zero dose?

• A. Nonlinear Hypothesis
• B. LINEAR Hypothesis
• C. Quadratic Hypothesis
• D. Exponential Hypothesis

Answer: (B)

The key idea is that the effect is directly proportional to the dose across the tested range, so a straight-line relationship lets you extend high-dose data down to lower doses and even to zero. This is the Linear Hypothesis: the dose–response is linear, meaning doubling the dose doubles the effect, and measurements at high dose-rate can be extrapolated to predict outcomes at low or zero doses. If the relationship were quadratic or exponential, the curve would bend or accelerate, and you couldn’t reliably extend the high-dose results to zero without introducing error. The linear model provides the simplest, proportional link between dose and effect, which is why it’s the best choice here.