*4.3.1 Trueness (homogeneity): z-score (for panels)*

The calculation of the *z*-score for panels focuses on the difference between onepanel result (median) and a reference result (median) in relation to a defined SD of *Sensory Evaluation of EVOO: Do Different Test Locations Have a Relevant Impact on Data… DOI: http://dx.doi.org/10.5772/intechopen.102702*


**Table 14.**

*Mixed-model ANOVA for main defect (SOP versus DOP).*

0.7. The reference result (in this study) is defined as the mean over all four test results (DOP remote, DOP *in situ*, SOP remote, and SOP *in situ*).

*Z*-score = difference between one-panel result (median) and the reference result\* (median) in relation to SD.

\* Reference result = median of results from all four considered test situations (DOP remote, DOP *in situ*, SOP remote, and SOP *in situ*)


→ Proof of trueness/homogeneous results (statistically acceptable)

We can see in **Figures 13** and **14** for the attribute fruitiness, that for *in situ* testing as well as for remote testing, the *z*-Score of SOP is in line with the requirements, that is—well below warning (±2) and action limit (±3). This is the case for bitterness and pungency as well, but not shown here. Based on these findings, it can be concluded that results from SOP are homogeneous (in both test situations) and statistically acceptable (= aspect of trueness).

**Figure 13.** *z-Score (SOP) fruitiness—in situ (n = 9).*

```
Figure 14.
z-Score (SOP) fruitiness—remote (n = 9).
```