Premise:
"This excuse usually appears in the form of a corporate press release, because nobody can keep a straight face when it's spoken out loud."
Hypothesis: People find the excuse amusing when it's spoken aloud.

yes

Premise:
"He had already made his selection in the corral, though he had despaired of ever getting that animal at rope's end."
Hypothesis: He had selected from the animals in the corral, but had not been able to get a rope on it.

yes

Premise:
"Rothko's triumphantly tragic career resembles what Robert Lowell called the generic life of his own generation of poets."
Hypothesis: Rothko had a tragic career.
yes