How to use "mistaken" in a sentence

Thenardier looked puzzled for a moment, then said, 'Monsieur, I think you are mistaken.'

But perhaps they'd been mistaken when they identified the body

Bob shook his head in agreement, frowning, as if he was dismayed to think that he could be mistaken for a common thief.

"You must be mistaken," Elliot said.

if I'm not mistaken, it started at the same time the parietal spot first showed up on the X-rays."

'Oh, dear! I have been very mistaken...'

'Then if a lady - Miss Hartnell perhaps - said that she came here about six o'clock, rang the bell, but got no answer - you would say she was mistaken?'

And if I'm not mistaken, you'll show how strong you are too

But, when he and the doctor were outside the house, the Count changed his mind and sent the doctor away, saying that he'd been mistaken.'