Learning Materials
Features
Discover
Chapter 5: Q2P (page 114)
What are the three parts of quality assurance? What questions are asked in each part and what actions are taken in each part?
The three parts of quality assurance are objectives, specifications and assessment.
Over 30 million students worldwide already upgrade their learning with 91影视!
All the tools & learning materials you need for study success - in one app.
Get started for free
Correlation coefficient and Excel graphing. Synthetic
data are given below for a calibration curve in which random Gaussian
noise with a standard deviation ofwas superimposed on
y values for the equation
. This exercise shows that
a high value of
does not guarantee that data quality is excellent.
(a)Enter concentration in column A and signal in column B of a
spreadsheet. Prepare an XY Scatter chart of signal versus concentration
without a line as described in Section
. Use LINEST
(Section 4-7) to find the least-squares parameters including
.
(b)Now insert the Trendline by following instructions on page 88.
In the Options window used to select the Trendline, select Display
Equation and Display R-Squared. Verify that Trendline and LINEST
give identical results.
(c)Add confidence interval y error bars following the instructions
at the end of Section 4-9. The
confidence interval is 6tsy,
where
comes from LINEST and Student鈥檚 tcomes from Table 4-4
forconfidence and
degrees of freedom. Also, compute
t with the statement .
Blind Samples: Interpreting Statistics-- The U.S. Department of Agriculture provided homogenized beef baby food samples to three labs for analysis.Results from the labs agreed well for protein, fat, zinc, riboflavin, and palmitic acid. Results for iron were questionable: Lab A, (13); Lab B, (8); Lab C, (3) mg/100 g . Uncertainty is the standard deviation, with the number of replicate analyses in parentheses. Use two separate t tests to compare results from Lab Cwith those from Lab A and Lab B at the 95 % confidence level. Comment on the sensibility of the t test results and offer your own conclusions.
Standard addition. An unknown sample of gave a current of in an electrochemical analysis. When of solution containing role="math" localid="1654761474124" was added to of unknown, the current increased to .
(a) Denoting the initial, unknown concentration as , write an expression for the final concentration, , after role="math" of unknown were mixed with of standard. Use the dilution factor for this calculation.
(b) In a similar manner, write the final concentration of added standard , designated as .
(c) Findin the unknown.
Detection limit. In spectrophotometry, we measure the concentration of an analyte by its absorbance of light. A low-concentration sample was prepared and nine replicate measurements gave absorbances of 0.0047,0.0054,0.0062,0.0060,0.0046,0.0056,0.0052,0.0044, and 0.0058. Nine reagent blanks gave values of 0.0006,0.0012, 0.0022,0.0005,0.0016,0.0008,0.0017,0.0010, and 0.0011.
a) Find the absorbance detection limit with equation 5-3.
b) The calibration curve is a graph of absorbance versus concentration. Absorbance is a dimensionless quantity. The slope of the calibration curve is Find the concentration detection limit with Equation 5-5.
(c) Find the lower limit of quantitation with Equation 5-6.
What is the difference between a calibration check and a performance test sample?
What do you think about this solution?
We value your feedback to improve our textbook solutions.
Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine