As shown above, a point estimate of the cross-over point C is simple to compute using Equations 1 and 4 or Equations 2 and 6, but an interval estimate is more difficult to compute. Using Equation 10, the SE of Ĉ can be used to calculate an interval estimate (e.g., a 95% CI); estimation of SEs of parameters in Equations 1, 2, and 10 is discussed in supplemental material.3
