The phrase "extremely probable" is correct and commonly used in written English.
It can be used to describe a situation or event that is highly likely or almost certain to occur. Here is an example sentence: - It is extremely probable that she will win the election, as she is currently leading in all polls.
"Severe disruption to roads and airports is extremely probable during the peak of the Monday afternoon rush hour," said Tom Defty, head of forecasting operations at MetService.
It appeared to me extremely probable that the same explanation would hold good for the twisted wing of the ash fruit.
"It is extremely probable that the aircraft was shot down by mistake by the Czechoslovak air force and in order to cover it up the secret police conceived the record plunge," Hornung said.
Although it is extremely probable that the United States and South Korea would quickly defeat North Korea's air force, Kim Jong Un's ground-based artillery and missile strikes could make it hard for the U.S. military to evacuate its wounded.
As he noted towards the end of the next century, "… if, by the term elements, we mean to express those simple and indivisible atoms of which matter is composed, it is extremely probable we know nothing at all about them" (1789, p. xxiv).
It seems to me that Boltzmann here adopts an (implicit) identification of probability and relative duration, At the very least, he does not indicate any difference in meaning between phrases like "During the greater part of that time, $H$ will be very near to its minimum" and "It is extremely probable that $H$ lies near its minimum".
"This sounds highly probable".
That seems highly probable.
Citing that Atta connection and other information the panel could not disclose, Commissioner Richard Ben-VenisaidsaIt: "is is extremely possible and perhaps probable that [Al-Qahtani] was to be the 20th hijacker". The Saudi withdrew his application for entry.
In addition, as observed here, it is extremely difficult to identify probable contacts retrospectively among patients who have difficulty communicating.
In that case we might expect a mean of reading skills scores that is close to 100 to be more probable than extremely low or high scores.
