Equation (2), page 4 from Bluck, "Recent advances in the interpretation of the 13C octanoate breath test for gastric emptying"

## Arguments

- minute
time in minutes

- dose
in mg

- cf
named vector of coefficients; only

`k`

and`beta`

are required. Note that`k`

is measured in 1/min (e_g_ 0_01/min), while often it is quoted as 1/h (e_g_ 0_6/h).