Question 326450
Your values range from -7 to 9, that's 16 spots.
You have 13 ticks so you can't have a spacing of 1.
Why don't you start at -12 and have a spacing of 2.
(-12,-10,-8,-6,-4,-2,0,2,4,6,8,10,12)
Then you'll be able to fit all of your data.