Reasoning Ability
Syllogism

All innovations are risky, but we only know some risky ventures fail. We cannot establish that the innovations which are risky are necessarily among those risky ventures that fail.

All flowers are plants, all plants require sunlight. Since some things requiring sunlight are expensive, it's possible that some flowers (being things requiring sunlight) are expensive.

We know some educated people are rich and no rich person is unhappy. Since some doctors are educated (subset), some doctors could be among those rich people, making them not unhappy.

While some problem solvers are not creative, some software engineers might still be creative - this is possible but not definite.

Since all X are Y and no Y is Z, by logical deduction, no X can be Z.

While no student is lazy, and lazy people are unsuccessful, this doesn't tell us about unsuccessful students who might be lazy or for other reasons.

Since some decision makers are not politicians, and all leaders are decision makers, some leaders must not be politicians.

Since no criminal is honest, it means all criminals must be dishonest (contrapositive of the first statement).

Although all gold is precious, only some precious things are expensive, so we cannot definitively conclude gold is expensive.

From two 'some' statements, we cannot draw a definite conclusion about the relationship between singers and actors.