 Solution

The measured decay is approximately consistent with the predicted $198{\mathrm{s}}^{-1}$ loss rate. Following rapid singlet-to-triplet population transfer, the unquenched phosphorescence intensity obeysA straight-line fit of $\ln I_P$ to the four times, expressed in seconds, givesThis differs from $198{\mathrm{s}}^{-1}$ by about $1.7\%$. For example, using the first point and the predicted rate gives subsequent intensities about $67.3,55.2,45.3$, close to the supplied $66.3,56.2,45.3$. The data support the expected millisecond exponential decay to this precision. With no measurement uncertainties supplied, a formal statistical acceptance or rejection is not justified.