Question 1188012
the middle 20% is between the 40th and 60th percentiles or z=-0.253 to z=+0.253
0.253=(x-mean)/sd for upper limit
0.253=(x-9.5)/0.9
0.2280=x-9.5
x=9.7280 gms upper limit. Symmetrical here so lower limit is 9.2720 gms.
(9.2720, 9.7280) gms