1. explain the assumption of calculation the standard deviation of a
   calibration curve

2. comment the conclusion of a compliant result
   the measured content of identified analyte is less than the Decision Limit
   not present, or not identified or less than Decision Limit

3. conditions of using standard addition to quantitative analysis

4. relationship between accuracy and random error
                                     systematic

5. explain "ANOVA" is used for comparison of several means by comparing
   the variances