dp0609 - FEP - Universidade do Porto

(ASSETS, SALES and MKCAP), a significant presence of outliers is apparent
(e.g., EDP, Portugal Telecom, Sonae, Brisa), as the mean is substantially
higher than the median. In relation to the ER variable, such difference is small,
the sample only experiencing here a slight positive asymmetry. Regarding
ROA, one can observe a mean asset profitability of 3%, with more than 50%
of the observations exhibiting profitability ratios lower than 5%. In what
concerns growth opportunities (proxied by PBV), our results show that the
market prices firms’ equity at a mean (median) premium of 83% (28%) over its
book value.
5.4. Group comparisons and correlation matrix
In table 7 a comparison is made between the two types of auditor
opinions according to a number of different variables. The results point to the
inexistence of significant differences between the two groups as far as board
size (NUM) or the number of board meetings (MEET) are concerned.
Regarding the percentage of non-executive board members
(PNEXEC), we find that the mean and median values for this variable are
lower in instances where a modified opinion has been issued, but such
difference is only marginally significant (p-value of 0.15). However, if one
considers a one-sided test – which is justifiable on the grounds that one would
expect a larger proportion of non-executive members in the clean opinion
group – the difference becomes statistically significant at the 10% level (p-
value