I think the difficulty of the below example, at least in my opinion is any probability you come up with off of simply those numbers will not be as high of quality(reliable) as if you filtered it with something or another specific addition.
In your example from the open of the first to the close on the last you have a pretty decent range of .0179 or 179 pips.
Based simply on those numbers I think your best chance is to go off of variance or standard deviation. So you could say from the most recent close what is the probability that it hits a certain price based on the average standard deviation of the previous 4 bars. Again I still feel like just doing that would be somewhat hard to predict a trend, even though obviously if the trend is down(up) it is likely to continue until it doesn't.
range of 1st bar:181 pips
range of 2nd bar: 70 pips
range of 3rd bar: 177 pips
range of 4th bar: 120 pips
Average range is 137 pips based on that sample.
Variance
(181-137)^2=1936
(70-137)^2=4489
(177-137)^2=1600
(120-137)^2=289
ave variance 2078.5?
I could be going about this all wrong, when would you plan to open your position? At the open of the next bar? If you assume you opened your position at the open of each bar you would have a 25% chance of being right long, and a 75% chance of being right short(going off of open to the high, and open to the low). The reason I ask is depending on the trend you would have a much higher chance of being right(in this case you are in a downtrend with a much higher chance of shorting at the open). This is why I was saying it would be good to filter it. obviously until the 4th bar you don't know the probability, and you certainly don't know it at the first bar unless you have a better reference.
The trend will persist until it doesn't but again, I feel like to increase your chance of being right you have to consider the duration or distance of the trend move in comparison to average, because if say on average a trend lasts 200 pips, you may not like the risk of opening a trade in that direction, but if it lasts 500 pips you would likely want to stick with the trend.
Let me break out some books and see if I can come up with an actual good answer instead of stating the obvious.

I'll let smarter people attempt to help you, haha.
Ben