ACS Analytical Chemistry Exam
Questions and Correct Answers
100% Verified Graded A+
1. standard deviation (s)
Answer> the square root of the variance
2. % relative standard deviation (%RSD)
Answer> Standard deviation divided by mean times 100
3. Grubbs test (Gcalc)
Answer> |Questionable value - mean/ std dev|
If that is larger than the Gtable value then the value is thrown out. Locate Gtable value based
on number of values in data set.
Used to define outliers
4. z score
Answer> (x- xavg)/s
5. F Test
1/
10
, Answer> used to compare precision
(s2)^2/(s1)^2 (should always be >1) Use n-1
to find on table.
Fcalc> Ftable -- There is some noise or error
6. External standard
Answer> use standard solutions spanning a range of conc, measure response
7. Internal standard
Answer> substance similar to analyte (ie deuterated); used to normalize signal by reducing
random error
8. Standard Addition
Answer> ideal for analyzing sample in a complex matrix; add known standard to constant
amount of sample; x-int =[sample]
9. Box car average
Answer> minimizes distance between data points and best fit line/ minimizes
standard deviation
10. Limit of detection (LOD)
Answer> 3*std dev
11. Limit of quantitation (LOQ)
2/
10
Questions and Correct Answers
100% Verified Graded A+
1. standard deviation (s)
Answer> the square root of the variance
2. % relative standard deviation (%RSD)
Answer> Standard deviation divided by mean times 100
3. Grubbs test (Gcalc)
Answer> |Questionable value - mean/ std dev|
If that is larger than the Gtable value then the value is thrown out. Locate Gtable value based
on number of values in data set.
Used to define outliers
4. z score
Answer> (x- xavg)/s
5. F Test
1/
10
, Answer> used to compare precision
(s2)^2/(s1)^2 (should always be >1) Use n-1
to find on table.
Fcalc> Ftable -- There is some noise or error
6. External standard
Answer> use standard solutions spanning a range of conc, measure response
7. Internal standard
Answer> substance similar to analyte (ie deuterated); used to normalize signal by reducing
random error
8. Standard Addition
Answer> ideal for analyzing sample in a complex matrix; add known standard to constant
amount of sample; x-int =[sample]
9. Box car average
Answer> minimizes distance between data points and best fit line/ minimizes
standard deviation
10. Limit of detection (LOD)
Answer> 3*std dev
11. Limit of quantitation (LOQ)
2/
10
