(a)
Interpretation:
The following data is obtained from the several food plant preparations for potassium ion-
Samples | |
1 | 5.15,5.03,5.04,5.18,5.20 |
2 | 7.18,7.17,6.97 |
3 | 4.00,3.93,4.15,3.86 |
4 | 4.68,4.85,4.79,4.62 |
5 | 6.04,6.02,5.82,6.06,5.88 |
The value of mean and standard deviation for each sample is to be determined.
Concept introduction:
The following formula will be used-
Mean-
Or
Deviation-
(b)
Interpretation:
The following data is obtained from the several food plant preparations for potassium ion-
Samples | |
1 | 5.15,5.03,5.04,5.18,5.20 |
2 | 7.18,7.17,6.97 |
3 | 4.00,3.93,4.15,3.86 |
4 | 4.68,4.85,4.79,4.62 |
5 | 6.04,6.02,5.82,6.06,5.88 |
The value s pooled,
Concept introduction:
The following formula will be used-
(c)
Interpretation:
The following data is obtained from the several food plant preparations for potassium ion-
Samples | |
1 | 5.15,5.03,5.04,5.18,5.20 |
2 | 7.18,7.17,6.97 |
3 | 4.00,3.93,4.15,3.86 |
4 | 4.68,4.85,4.79,4.62 |
5 | 6.04,6.02,5.82,6.06,5.88 |
The reason for the
Concept introduction:
The following formula will be used −
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Chapter A1 Solutions
Principles of Instrumental Analysis
- Estimate the absolute standard deviation (or uncertainty) for the results of the following calculations. Round each result so that it contains only significant digits. The numbers in parentheses are absolute standard deviations. Show your solution and express the final answer and its corresponding uncertainty. a) y= 2.998(±0.002) - 3.98 (±0.15) + 9.035 (±0.002) = 8.0531 b) y= 39.2(±0.3) x 3.054 (±0.022) x 10^ -2 = 1.197 c) y= [198(±6) - 89 (±3)] / 1335 (±2) + 64 (±7)] = 7.791 x 10^-2arrow_forward3) For the results, discuss the significance of the following in terms of accuracy or precision: a) Deviation vs Absolute Error. b) % Error vs Standard Deviation.arrow_forwardA 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
- Analysis of several plant-food preparations for potassium ion yielded the following data: Sample Percent K+1 6.02, 6.04, 5.88, 6.06, 5.822 5.29, 5.13, 5.14, 5.28, 5.20 The preparations were randomly drawn from the same population.(a) Find the mean and standard deviation s , variance , andCV for each sample.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_forwardA 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?arrow_forward
- A loss of 0.35 mg of Zn occurs in the course of analysis to determine the element. Calculate the percent relative error due to this loss if the masses of Zn in the replicate samples are the ff: (a) 40.0 mg (b) 400.0 mg (c) 175.0 mg (d) 600.0 mg.arrow_forwardA volumetric calcium analysis on triplicate samples of the blood serum of a patient believed to be suffering from a hyperparathyroid condition produced the following data: mmol Ca/L = 3.55, 3.65, 3.14. What is the 95% confidence interval for the mean of the data, assuming(a) No prior information about the precision of the analysis?(b) s → σ = 0.056 mmol Ca/L?arrow_forwardConsider the following sets of replicate measurements: (1) Calculate the mean and standard deviation of Group A. (2) Determine the confidence interval at 95% confidence level. Assume the data here are the only knowledge you have and no previous measurements are available.arrow_forward
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- Principles of Modern ChemistryChemistryISBN:9781305079113Author:David W. Oxtoby, H. Pat Gillis, Laurie J. ButlerPublisher:Cengage Learning