You will see a higher gage reading (lower vacuum/higher absolute pressure) with the throttle valve open than you will with it closed.
The manifold absolute pressure is less related to crankshaft speed than throttle valve opening, I think you'll find. Granted, the engine will move more air per unit time when running faster, but it is the throttle valve that proves the ultimate bottleneck when it comes to moving air (and the only one you can adjust easily. There are, of course, others - most notably the intake opening (throttle body) and the cylinder head ports/runners.)
You'll see "higher" readings in the sense that you're going to see higher manifold absolute pressure (measuring from 0m/m Hg, or psia - pounds per square inch, absolute) yet the manifold pressure is still going to be "below atmospheric) (measuring from ~760m/m Hg:1bar:14.7psia:760 Torr, or psig - pounds per squar inch, gage.)
The principal difference between "psia" and "psig" is where you start counting - with psig, you're starting at ~14.7psi, or atmospheric pressure (14.69... psi @ STP, as I recall.) "High vacuum" is a low gage reading on the absolute scale, or a greater difference between atmospheric/normal pressure and pressure as observed. "Low vacuum" is a high gage reading on the absolute scale - with "no vacuum" being one atmosphere or 760m/m Hg.
So, it seems counter-intuitive at first, until you get used to the two scales. Check your automotive programme (I'm assuming you're dealing with secondary education?) for a "sidebar" course in something like "Automotive Mechanisms" - you'll pick up a fair bit taking that course. Pressure/vacuum, mechanical advantage of various lever and pully systems, elementary fluid power - all the sort of stuff we covered in high school phyzzies 'way back when. (Pity they don't do that in primary education anymore. I had to take "Automotive Mechanisms" at De Anza - I could have taught the course off of what I'd learned in high school.)
Anyhow, you're probably not going to really dig into pressure/vacuum in an intro automotive course - just get into what causes manifold vacuum (and why!) and what it's used to control. More's the pity.
If you don't have that "sidebar" course I was talking about, you'll want to take a basic Physics course (which you probably need anyhow.) Everyone should be at least "grounded" in physics, chemistry (at least inorganic,) and maths - then you can branch off into things like organic chemistry, petrochemistry, geology, optics (what fun!), aerospace, metallurgy, and such. But, if you don't know the basic "whats" and "whys" of how the world works, you're going to be well behind the curve...
Meanwhile, tell you what - see if you can explain what I'd just said about vacuum back to me (without looking!) and I'll see if you've got it. Assume, when writing, that I don't know anything about the subject, and you're trying to explain it to me.
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