analytical chem ttu

analytical chem ttu exam 1 Questions And Answers 2025/2026




accuracy - CORRECT ANSWER-degree of agreement between measured value and
true value


precision - CORRECT ANSWER-degree of agreement between the replicate
measurements


does good precision ensure good accuracy? - CORRECT ANSWER-no


aboslute error - CORRECT ANSWER-difference between measured (Xi) and true
value (Xt)
E= Xi-Xt


Relative Error - CORRECT ANSWER-% between measured (Xi) and true value (Xt)
Er=((Xi-Xt)/Xt))x100


deviation - CORRECT ANSWER-Di = | Xi - X$ |


random / indeterminate error - CORRECT ANSWER-causes data to be scattered
around mean value
affects precision

, caused by uncontrollable variables


systematic / determinate error - CORRECT ANSWER-causes mean of data to differ
from accepted value
affects accuracy


gross error - CORRECT ANSWER-occasional, large
often human error
outlier: results that differ markedly from replicates


systematic errors (bias) - CORRECT ANSWER-definite value, reproducible
sources
- instrument error
** instabilities , inappropriate conditions
-method error
** non-idea behavior, interferences
- personal error
** careless / limitations
** bias


constant error - CORRECT ANSWER--absolute error constant with sample size
-relative error varies w/ sample size
** excess reagant required for color change during titration. more significant at
smaller sizes