Page 27 - Statistics presented by Dr. Sara Ismail Aborass

9/8/2023

Conclusion

 Correlation is a statistical technique used to determine the
type and strength to which two variables are related.

 Linear relation  r indicates type (+, -) and strength (strong or
weak)

51

ERRORS in CHEMICAL ANALYSIS

Error is the collective noun for any departure of the result from the "true“
value.

Analytical errors can be:
1. Random (Indeterminate) or unpredictable deviations between replicates,

quantified with the "standard deviation". Data scattered approximately
symmetrically about a mean value. Affects precision .
2. Systematic (Determinate) or predictable regular deviation from the
"true" value, quantified as "mean difference" (i.e. the difference between
the true value and the mean of replicate determinations). Several possible
sources. Readings all too high or too low. Affects accuracy.
3. Gross Errors.

52

26