Can MPS be negative? 

no, because mpc + mps = 1.it cannot be negative.

no coz MPS is the ratio b/w change in savings and change in income which is always positive due to positive relationship b/w savings and income. Either both will increase or both will decrease which will give the net result as positive.

Also MPS = 1-MPC and MPC is always less than 1. So MPS is always positive.

 mps is always positive and only aps can be positive zero or even negative 

for futher reference go to the study material of meritnation

No! Mps ALWAYS lies between 0 to1