I'm not going to search for highly scientific and technical terms. I just want to know the following:

We have a relatively considerable downtrend stock that is suddenly showing a massively high volume change. Does this mean the stock is being bought by huge institutions (mutual funds)? If yes, this logically consolidates the stock and gives it support to start a significant uptrend move, doesn't it?

And is the opposite also true? When we have a stock that has been on the rise for a relatively considerable period and now, suddenly, after a lot of action spotted in its volume, the stock begins its downtrend, does this mean the same institutional owners and other traders are losing confidence in the stock? Is the price of a stock pushed upward or downward in relation to the number of people or institutions that own it? Does the volume of a stock only show sheer speculation about that stock?

Also, why should I care, in a stock chart, about the P-E ratio? If I know the price of the stock and its EPS, what use can the P-E ratio be? Or is it only there so that you may compare it with the company's previous P-E ratio, kind of like the EPS?