change speed through gui for a model?

so i am trying to make a horse game, i tried making a gui to change speed for the horse when riding but nothing happened when i pressed it this is the scripts i used

script.Parent.MouseButton1Click:Connect(function() game.Workspace.base.Humanoid.Walkspeed = 16

end) for walking gui and

script.Parent.MouseButton1Click:Connect(function() game.Workspace.base.Humanoid.Walkspeed = 32

end)

for running gui

whats the problem :)?> > [](http://)