Principles of Instrumental Analysis
7th Edition
ISBN: 9781305577213
Author: Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Question
Chapter A1, Problem A1.16QAP
Interpretation Introduction
Interpretation:
In a NIST reference steel sample the certified percentage of nickel is 1.12% and the standard deviation related to this 0.03%. The determination of percentage produce for the nickel using new spectrometric method is − 1.10, 1.08, 1.09, 1.12 and 1.09. The indication of the bias in the method at the 95% level is to be determined.
Concept introduction:
The formula that will be used-
Here,
N = degree of freedom
s = standard deviation
t = constant
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
8) Two different analytical methods are compared for determining Ca. The following
are two sets of data.
Set 1
Set 2
155.779
155.784
155.787
155.787
155.813
155.765
155.781
155.793
i.
i.
Determine the mean and the standard deviation in Set 1.
Calculate the 95% confidence limit for data in Set 1.
Identify a possible outlier in Set 2. Use the Q-test to determine whether it
can be retained or rejected at 95% confidence level.
ii.
:0.29 µg Cu/mL (s → ơ). The analysis of an oil from a reciprocating aircraft
An atomic absorption method for determination of copper in fuel samples yielded a pooled standard deviation of spooled
engine showed a copper content of 8.03 ug Cu/mL. Calculate the 95 and 99% confidence intervals for the result if it was based on
(This problem requires values in your textbook's specific appendices, which you can access through the OWLV2 MindTap Reader. You should not use the OWLV2 References' Tables to answer this question
as the values will not match.)
a a single analysis
95% confidence interval = 8.03 +
µg Cu/mL
99% confidence interval = 8.03 ±
ug Cu/mL
b the mean of 5 analyses
95% confidence interval = 8.03 +
| ug Cu/mL
99% confidence interval = 8.03 ±
µg Cu/mL
c the mean of 15 analyses
95% confidence interval = 8.03 +
ug Cu/mL
99% confidence interval = 8.03 ±
ug Cu/mL
A titrimetric method for the determination of calcium in limestone was tested with the analysis of a NIST limestone containing 30.15% CaO. The mean of the four analyzes is 30.26% CaO with a standard deviation of 0.085%. From the data accumulated from many analyzes, s→ϭ=0.094% CaO was found.a) Do the data indicate the presence of systematic error at the 95% confidence level?b) When a value for ϭ is unknown, do the data show a systematic error at the 95% confidence level?
Chapter A1 Solutions
Principles of Instrumental Analysis
Ch. A1 - Prob. A1.1QAPCh. A1 - Prob. A1.2QAPCh. A1 - Prob. A1.3QAPCh. A1 - Prob. A1.4QAPCh. A1 - Prob. A1.5QAPCh. A1 - Prob. A1.6QAPCh. A1 - Prob. A1.7QAPCh. A1 - Prob. A1.8QAPCh. A1 - Prob. A1.9QAPCh. A1 - Prob. A1.10QAP
Ch. A1 - Prob. A1.11QAPCh. A1 - Prob. A1.12QAPCh. A1 - Prob. A1.13QAPCh. A1 - Prob. A1.14QAPCh. A1 - Prob. A1.15QAPCh. A1 - Prob. A1.16QAPCh. A1 - Prob. A1.17QAPCh. A1 - Prob. A1.18QAPCh. A1 - Prob. A1.19QAPCh. A1 - Prob. A1.20QAPCh. A1 - Prob. A1.21QAPCh. A1 - Prob. A1.22QAPCh. A1 - Prob. A1.23QAPCh. A1 - Prob. A1.24QAP
Knowledge Booster
Similar questions
- A titrimetric method for the determination of calcium in limestone was tested by analysis of an NIST limestone containing 30.15% CaO. The mean result of four analyses was 30.26% CaO, with a standard deviation of 0.085%. By pooling data from several analyses, it was established that s = 0.094% CaO.a. Do the data indicate the presence of a systematic error at the 95% confidence level?b. Do the data indicate the presence of systematic error at the 95% confidence level if no pooled value for s was available?arrow_forwardA 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_forwardasaparrow_forward
- A clinical chemist obtained the following data for the alcohol content of a sample of blood: % C2H5OH: 0.084, 0.089, and 0.079. Calculate the 95% confidence interval for the mean assuming that (a) the three results obtained are the only indication of the precision of the method and that (b), from previous experience on hundreds of samples, we know that the standard deviation of the method s 5 0.005% C2H5OH and is a good estimate of s.arrow_forward[References) A method for the determination of the corticosteroid methylprednisolone acetate in solutions obtained from pharmaceutical preparations yielded a mean value of 3.7 mg mL with a standard deviation of 0.3 mg mL. For quality control purposes, the relative uncertainty in the concentration should be no more than 3%. How many samples of each batch should be analyzed to ensure that the relative standard deviation does not exceed 9% at the 95% confidence level? samplesarrow_forwardCalculate the standard deviation for an element whose % in a sample were found to be20.8, 21.6, 22.1, 22.0, 23.3, 21.9 and 22.8%arrow_forward
- An analysis of a sample containing mercury was performedusing a standard procedure and a new procedure. The samplewas analyzed 6 times by the new procedure and 8 times by thestandard procedure resulting in standard deviations of 0.355 and0.524 for the new and standard procedures, respectively. If thepooled standard deviation for the data was 0.66 and thetabulated F value at the 95% confidence level was 4.88, Thefollowing statement(s) are true:Select one or more:A. The calculated F value is 2.179B. We are confident that there is no significant statisticalC. difference between the results of the two methodsD. There is no significant statistical difference between theprecision of the two methodsThe calculated F value is 3.216arrow_forwardReplicate tests showed the following lead content results of a blood sample: 0.752, 0.756, 0.752, 0.751, and 0.760 ppm Pb. Calculate the (a) the mean (b) the standard deviation (c) the variance (d) the relative standard deviation in parts per thousand, (e) the coefficient of variation, and (f) the spread.arrow_forwardFor the determination of iron in used jet engine oil, 30 analyzes with 3 repetitions each were made by atomic absorption method and the standard deviation was found s=2.4 µg Fe/mL. Since this standard deviation value is close to the ϭ value, the iron concentration of 18.5 µg Fe/mL(a) by a single analysis,(b) as the average of the two analyzes,(c) Calculate the 80% and 95% confidence intervals if found as the mean of four analyses.arrow_forward
- Calculate the sample standard deviation, s, for this set of data: 5.2, 7.8, 8.6, 9.6, 2.0, 8.7 Report your answer to the fourth decimal place.arrow_forwardAn atomic absorption method for the determination of the amount of iron present in used jet engine oil was found from pooling 30 triplicate analyses to have a standard deviation s = 3.1 µg Fe/mL. If s is a good estimate of o, calculate the 95 and 99% confidence intervals for the result 21.7 µg Fe/mL if it was based on the following criteria. (a) a single analysis 95% confidence interval= 21.7 + 99% confidence interval = 21.7 + (b) the mean of two analyses 95% confidence interval = 21.7 + 99% confidence interval= (c) the mean of six analyses 21.7 ± 95% confidence interval = 21.7 + 99% confidence interval= 21.7 + μg Fe/mL μg Fe/mL μg Fe/mL μg Fe/mL μg Fe/mL μg Fe/mLarrow_forward
arrow_back_ios
arrow_forward_ios
Recommended textbooks for you
Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning