Measurements of the activity A (in counts per minute) of a radioactive sample are plotted as ordered pairs (t,lnA), where t is measured in days. A least–squares regression gives lnA=4.10−0.085t. Which statement best interprets the numerical value 4.10?
a) 4.10 is the decay constant of the sample, measured in reciprocal days.
b) It is the natural logarithm of the predicted initial activity of the sample.
c) It equals the half–life of the sample, expressed in days.
d) It is the predicted initial activity of the sample, measured in counts per minute.