The original results of the measured values of β must now be reexamined. The results from Table 8.3 are plotted as a function of temperature in Figure 8.12, with 95% uncertainty limits on each data point. Clearly, there is no justification for assuming that the measured values indicate a trend of changes with temperature, and it would be appropriate to use either the average value of β or the value determined from the linear least-squares curve fit.