The weight of a bag of corn chips is normally distributed wi
The weight of a bag of corn chips is normally distributed with a mean of 22 ounces and a standard deviation of
Solution
mean = 22 oz
sd = 0.5 oz
a.
x1 = 21.2
z1 = (x-mean)/sd = (21.2-22)/0.8 = -1.6
P(z<-1.6) = 0.0548
so, 5.48%
b.
x2 = 21.7
z2 = (21.7-22)/0.5 = -0.6
P(z>-0.6) = 1 -P(z<-0.6) = 1 - 0.2743 = 0.7257
c.
x3= x3
z = z3
P(z>z3) = 0.2
P(z<z3) = 1 - P(z>z3) = 1 - 0.2 = 0.8
P(z<z3) = 0.8
z3 = 0.84
x3 = 22 + 0.84*0.5 = 22.42 oz
d.
x4=21 oz
z4 = (21-22)/0.5 = -2
P(z<-2) = 0.0228
so, 2.28% of bag weight less than 21 oz
so, it not accepted as per FDA standards because it limits to 1% only.
x5 =21
now to minimize dispersion, new standard deviation to be applied,
so sd=sd2
z5 = (21-22)/sd2 = -1/sd
P(z<z5) = 0.01
z5 = -3.09
-1/sd2 = -3.09
sd2 = 1/3.09
sd2 = 0.3236
in order to maintain FDA norms, dispersion to be minimised to 0.3236 oz.

