(a)
Interpretation:
The counting rate 9cpm is the background counting rate in the laboratory which was measured at the time period of 3 min and it is required that the value of standard relative deviation should be less than the 5%
Concept introduction:
The formula for the standard deviation for the corrected counting rate is given as-
Where,
Relative standard deviation is represented by the following formula-
Also,
(b)
Interpretation:
The counting rate 9cpm is the background counting rate in the laboratory which was measured at the time period of 3 min and it is required that the value of standard relative deviation should be less than the 5%
Concept introduction:
The formula for the standard deviation for the corrected counting rate is given as-
Where,
Relative standard deviation is represented by the following formula-
Also,
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Principles of Instrumental Analysis
- A solution is prepared by weighing 5.0000 g of cesium iodide into a 100-mL volumetric flask. The balance used has a precision of 0.2 mg reported as a standard deviation, and the volumetric flask could be filled with a precision of 0.15mL also reported as a standard deviation. What is the estimated standard deviation of concentration (g/mL)?arrow_forwardYou are developing a procedure for determining traces of copper materials using a wet digestion followed by measurement by atomic absorption spectrophotometry. In order to test the validity of the method, you obtain an NIST orchard leaves standard reference material and analyze this material. Five replicas are sampled and analyzed, and the mean results are found to be 10.8 ppm with a standard deviation of plus or minus 0.7. ppm. The listed value for the standard reference is 11.7 ppm. Does your method give a statistically correct value at the 95% confidence level?arrow_forward6 A new method for the determination ofanthracene in crude oil is in the developmental phase. Preliminary results using the new method give a standard deviation of 3 ppm when 5 replicates are used. The ‘traditional’ method gives a standard deviation of 7 ppm when 4 replicates are used. Is there a significant difference in the standard deviations for these methods at 95% CL?arrow_forward
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- Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning