The function f(x)=16sinx contains which type of transformation or change to its parent graph? phase shift, vertical shift, horizontal stretch or change in period, vertical stretch or change in amplitude

The parent graph would be f(x) = sin(x).

The 16 coefficient represents a vertical stretch because the y-values of the graph expand out further. That is, on the parent graph, f(pi/2) = 1 while on the the function 16sin(x), f(pi/2) = 16. As you can see the graph is stretched out vertically.