Answer:
the scale factor is the vertical expansion factor.
Explanation:
The scale factor of 2 in
g(x) = 2·F(x)
means g(x) is a vertical expansion (not shrink) of F(x) — by a factor of 2.
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Additional comment
The equation g(x) could be considered to be ...
g(x) = F(x·√2)
in which case g(x) could be interpreted as a horizontal shrink by a factor of (√2)/2. Squeezing a parabola horizontally has the same effect on its appearance as stretching it vertically.