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Alcohols pKa, Amines pKb and Carbocations. Why is the "CH3" methyl group so weird?

It is known, experimentaly, that terciary carbocations are "more stable" than secudary ones, which are more stable than primary ones:

masterorganicchemistry.files.wordpress.com

I was told that this was due to the "Methyl group induction", basically meaning that the "CH3" works as a way to "give" some electrons to its neighbor carbocation, increasing its ...

It is known, experimentaly, that terciary carbocations are "more stable" than secudary ones, which are more stable than primary ones:

masterorganicchemistry.files.wordpress.com

I was told that this was due to the "Methyl group induction", basically meaning that the "CH3" works as a way to "give" some electrons to its neighbor carbocation, increasing its stability.
Based on that, one can deduce that, when comparing electronegativity, a Methyl group would be less electronegative than a Hydrogen:
Ch3 < H {Electronegativity}

My question is more of a "confirmation". Based on Wikipedia, we have the following pKa for alcohols:

Methanol: 15.5 - https://en.wikipedia.org/wiki/Methanol
Ethanol: 15.9 - https://en.wikipedia.org/wiki/Ethanol
Isopropanol: 16.5 - https://en.wikipedia.org/wiki/Isopropyl_alcohol
T-Butanol: 16.54 - https://en.wikipedia.org/wiki/Tert-Butyl_alcohol

Is the deacresing acidity due to the presence of Methyl groups? As they act to increase the electron density to the carbon associated to the Hydroxy OH group, therefore increasing the energy necessary to liberate its H+?

Now, with the pKb for amines:

NH3: 4,75
Methylamine: 3,36
Dimethylamine: 3,29
Trimethylamine: 4,19

As one could judge, all fine in the beggining: the more Methyl groups, the more electrons the amine can receive and the more "basic" it gets. Until it does NOT:

Why is Trimethylamine so "Acid" if it has 3 Methyl groups?!?!

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