1st one is in a range of 19k -24k mean = 21.5k s.d = 2k for this i get -1.25 and 1.25

2nd one same range but mean is 21.8 and sd = 1k

for this i get

__19-21.8 =__-2.8 then

__24 -21.8 =__2.2

1 1

in my text book im told to have the mean as the centre point and use s.d as each unit on the x axis but the 2 will look a little different as im trying to make them equal across the X axis and stick to their s.d units.

Hope this makes sense, ive been stuck on this all day