Answer:
The function will have a vertical compression when 0 < α < 1
Explanation:
The vertex form of a quadratic function showing the factors of the transformation of the function, is presented as follows;
The vertical scaling of the function (compression and stretching) is given by the value of the α control coefficient
A vertical stretch occurs when α > 1, while a vertical compression occurs when 0 < α < 1
Therefore, in order for a quadratic function to have a vertical compression, 0 < α < 1.