actually my issue was that it was showing decimal point values on the y axis;
this answer didnt solve the purpose.
if i use minimumtickinterval / maximum tickinterval it will not stop showing the decimal values on the yaxis.
if i use mintickinterval of 3 it can show 4.5 on y axis.
i am lookin for right answer ASAP. its been so long since in raise this issue with screenshot