Appl Of Ms Excel In Analytical Chemistry
2nd Edition
ISBN: 9781285686691
Author: Crouch
Publisher: Cengage
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In replicate analyses, the carbohydrate content of a glycoprotein (a
protein with sugars attached to it) is found to be 12.6, 11.9, 13.0, 12.7,
and 12.5 g of carbohydrate per 100 g of protein.
(a) Find the mean of the measurements.
(b) Find the standard deviation (s).
(c) Find the 90% confidence intervals for the carbohydrate content.
(d) If the mean and s are unchanged, but there are 10 measurements
(N=10) instead of 5, what would be the confidence interval?
(e) How does increasing the number of replicate measurements
affect the reliability of measurements? Explain your answer. (Hint:
better precision gives smaller confidence intervals)
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.
The glucose concentrations in a patient with mildly elevated glucose levels were determined by a spectrophotometric analytical method and were recorded in mg/L as follows: 799, 745, 750, 774, 777, 800, 758 and the true value is 792. (a) Calculate the standard deviation
(b) Calculate the relative error in ppm
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