Normality:
To test for the normality of the data an Anderson-Darling test was used. The Anderson-Darling test is an ECDF (empirical cumulative distribution function) based test. The null hypothesis for this test is H0: data follow a normal distribution. If the p-value is less than the alpha level, reject H0.
"The data are plotted as the x-values. Minitab calculates the probability of occurrence, assuming a normal distribution, and plots the calculated probabilities as y-values. The grid on the graph resembles the grids found on normal probability paper, with a log scale for the probabilities. A least-squares line is fit to the plotted points and drawn on the plot for reference. The line forms an estimate of the cumulative distribution function for the population from which data are drawn. Minitab also displays the sample mean, standard deviation, and sample size on the plot." (Minitab Help File)
From these tests we can succesfully conclude that the data are normally distributed. Thus, tests assuming normality can be used.
