What does it mean to be plausible? (From Sinclair's The Jungle)

Apparently fair, reasonable, or valuable.

So this grim old woman went on with her tale of horrors. How much of it was exaggeration — who could tell? It was only too plausible. There was that about consumption, for instance. They knew nothing about consumption whatever, except that it made people cough; and for two weeks they had been worrying about a coughing-spell of Antanas. It seemed to shake him all over, and it never stopped; you could see a red stain wherever he had spit upon the floor.

From Upton Sinclair's The Jungle.