Results and Discussion

Statistical tests for normal distribution were conducted before any regression analysis. The Shapiro-Wilk method tests the null hypothesis that the data are normally distributed, and was selected due to the small number of samples, particularly after removing upper outlier values in the phase 2 data set. Normality tests are essential since many other statistical tests presume a normal distribution of data, notably the dependent variables in linear regression. Table 2 summarizes the results of the Shapiro-Wilk normality tests for both raw and trimmed data.
In the phase 1 data set, only density and three of the fifteen (20%) cannabinoids (CBCA, CBDA, CBNA) had a statistically normal distribution (p > 0.05). Conversely, the distribution was statistically normal for nine of fifteen (60%) of the analytes in the phase 2 data set. CBCA, CBC, CBD, CBL, CBN, and THC were not normally distributed in the phase 2 data set. The Shapiro-Wilk test showed increases in significance (p -values) for individual analytes in the phase 2 data set, but it was not enough to pass the normality test at 0.05 significance.
Table 2 (a-b): Shapiro-Wilk tests for normal distribution