How to pronounce $\chi^2$?

Question

When talking about the $\chi^2$-test or the $\chi^2$-distribution, my colleagues have different pronunciations of the letter $\chi$. How should it be pronounced?

I quickly found three different ways:

Kai-sound like in "kite": http://youtu.be/5_74FkJXG68?t=4s

Ch-sound like in "Loch Ness": http://youtu.be/EijkVbkPXT8?t=10m24s

He-sound like in "he": http://youtu.be/28yu1PFc438?t=3m45s

Answer 1

See the wikipedia article:

Chi (uppercase Χ, lowercase χ; Greek: χῖ) is the 22nd letter of the Greek alphabet, pronounced /ˈkaɪ/ or /ˈkiː/ in English.

So "kite"-like /ˈkaɪ/ is okay.
The traditional greek pronounciation is more like /ˈxiː/, so this is the origin of the "loch"-like pronounciation and the "he" in the linked YT video.

Note that this question is better suited for ELL.SE, since it's about language and not about Mathematics.