Table 1.

Distribution of responses over skills.

Skills	Skill description	N	Average	Standard dev
MppFd	Modus ponendo ponens with few disabling conditions	294	0.9456	0.16078
MppMd	Modus ponendo ponens with many disabling conditions	294	0.898	0.23726
MppCcf	Modus ponendo ponens at the counterfactual level	294	0.907	0.2394
MppA	Modus ponendo ponens at the abstract level	294	0.9615	0.16066
MttFd	Modus tollendo tollens with few disabling conditions	294	0.8435	0.26646
MttMd	Modus tollendo tollens with many disabling conditions	294	0.7925	0.29985
MttCcf	Modus tollendo tollens at the counterfactual level	294	0.7494	0.33326
MttA	Modus tollendo tollens at the abstract level	294	0.8401	0.28974
AcMa	Affirmation of the consequent with many alternatives	294	0.424	0.38072
AcFa	Affirmation of the consequent with few alternatives	294	0.3039	0.3652
AcCcf	Affirmation of the consequent at the counterfactual level	294	0.3345	0.40801
AcA	Affirmation of the consequent at the abstract level	294	0.2823	0.41038
DaMa	Denial of the antecedent with many alternatives	294	0.407	0.37389
DaFa	Denial of the antecedent with few alternatives	294	0.3027	0.35081
DaCcf	Denial of the antecedent at the counterfactual level	294	0.381	0.40662
DaA	Denial of the antecedent at the abstract level	294	0.305	0.42077

Skills difficult to master (Average <0.4) and skills easy to master (Average > 0.9) are in bold.