For a particular radioactive sample, the total counting rate (sample plus background) was 450 cpm, and this value was obtained over a 15.0-min counting period. The background was counted for 2.0 min and gave 7 cpm. Estimate
(a) The corrected counting rate Rc.
(b) The standard deviation associated with the corrected counting rate σRc.
(c) The 95% confidence interval associated with the corrected counting rate.