Table 4. Statistical Comparison of the Recommended Method with UV–Vis Reference Method for Fluoride Determination.
| method | mean conc. (mg L–1) | SD (σ) | Sa,b | ta,b | ttablob | Fb | Ftablob |
|---|---|---|---|---|---|---|---|
| recommended method | 12.621 | 0.134 | |||||
| UV–Vis reference method | 12.551 | 0.151 | 0.169 | 0.291 | 2.306 | 1.591 | 6.39 |
a
S2 = ((n1 – 1)s12 + (n2 – 1)s22)/(n1 + n2 – 2) and t = (a̅1 – a̅2)/(S(1/n1 + 1/n2)1/2), where S is the pooled standard deviation, s1 and s2 are the standard deviations of the two populations with sample sizes of n1 and n2, and a̅1 and a̅2 are sample means (t has (n1 + n2 – 2) degrees of freedom); here, n1 = n2 = 5.
b
Statistical comparison made on paired data produced with the proposed and reference methods; results given only on the row of the reference method.