Chapter 4 + 5 Flashcards
what is Grubbs test
Gcalc = |questionable value - x| / S
- if Gcalc is > Gtable throw the point out
What is Dixons Q test
Qcalc = gap/range
If I am doing an analysis with an instrument that is unstable over time, what type of
calibration should be run
calibration with internal standard
variance of a sample is equal to
the standard deviation squared
The limit of quantitation is equal to how many standard deviations above the mean for a
blank?
10
when is standard addition used
- is used when the sample matrix interferes with the analysis
- uses a standard that is the same compound as the analyte
- involves finding the x-intercept of the plotted data
Which of the following generally occurs at the highest concentration?
a. limit of quantitation
b. limit of detection
c. limit of linearity
d. they are all at the same concentration
c. limit of linearity
Internal standards are used in sample analysis when
the instrument is unstable over time
The total area under the standard error (Gaussian) curve is
1
Assuming an equal number of degrees of freedom, the size of a 95% confidence interval is
a. equal to a 50% confidence interval
b. smaller than a 50% confidence interval
c. larger than a 50% confidence interval
d. cannot compare the two without knowing the number of degrees of freedom
c. larger than a 50% confidence interval
calibration sensitivity is equal to
the slope (m)
An F test is used to determine the statistical equivalence of what quantity from two sets of
measurements?
variance
limit of quantitation
10sbl / m
limit of detection
3sbl / m
R^2 = 1 means?
completely linear
