Question

Could you please solve it as soon as possible for Radiation Health Physics.

9.8. A sample that had been counted for 15 minutes showed a mean counting rate of 32 cpm. The background, counted for 10 minutes, was 15 cpm. (a) What is the net counting rate, at the 95% confidence limit? (b) What is the coefficient of variation (relative error at ±1 standard deviation) of the

Answer 1

8olution a). net counting rate, at the 954 Canfidence linut from the data of normal distributian cusve at Lno af standasd devidtians 95.1. Confidence Linit we know trat devialian af net counting Sate s, taudaad th deviatian of grass Counting rad e stanhad standard deviation of hackgrouud cacuating rate uhere & gress Count ing rate rate =buckgroand Counetiy ta= time cuig which gross Count dene dusing whih backgond count done th time thele IS min given -that = 32 cpm, tg= YA rpIS cpm th10 min 32-15 14 cpmw. met= net court rade net= Cpm 32 tS 8/9191 fram eanO 15 OnI91 1.96 8tandasd daviationg at 95% cofi dence Limit cauting Ciet) ate at thes diutt is, 80 net Yt 1.960 16 C1.9 1) 7t 3 Cpm 17 3.34 Cpm Ynet

Coetficient of vasiatian Selative essog t 1standasd deviatton) twe know that Coeffiu'eut of vasiatian Ccv), to the net caurt yate, tnese Cfrom past@) tandaed deviadian CV= O=1.91 mean value 17 now ol.elattve psohable esco at t 1SD) ofocv hae I91X100 x100 11. 2.3% & n=17. CV = +0.23)1 foCv -23%