It can be predictable but not always but only if you found great project coin which is like example here in signature campaign then it would be great project,if coin owner advertise hard that coin,also buying top trending coins and sell later is really great strategy and really predictable.
We cannot know the exact amount but the market experts can predict based on the data they have if the price will going to rise or not.
The one that price depends is the number or users who are willing to buy is I think that is more unpredictable that is why trading is so risky. We cannot really tell the exact.
True , but still if we are working our job of trading with our own stretagy then we will get some extent profit without any much problem . So here I can't fully support that " trading is unpredictable job " .
But still in trading sometimes we got jackpot or got negative of jackpot due to rust of market and down of market respectively .
So it is to be better to buy those altcoins which are at the rate of 10-20 satoshi and thus when got fluctuate for high we will got profit but still if price goes down thestil we will not get much loss .
So some stretagy always results into the profit always , So here by using own mind we can change the job of trading into predictable job with maximum chances of getting profit .