Solution A:
X be the time required to build a computer
X » N (µ=50 : σ = 10)
P(45<X<60=F(60)-F(45) =
=ɸ (60-50/10) - ɸ(45-50/10) =
= ɸ(1)- ɸ(-0.5) =
=ɸ(1)-[1- ɸ(0.5)] =
= ɸ(1)+ ɸ(0.5)-1=
0.8413+0.6915-1=
=0.5328
Solution B
We want to find P(X>32) where X is normally distributed with (µ=32.2 : σ = .3)
Things we know,
P(X>32)= P(X- µx/ σx> 32-32.2/.087=P(Z>-2.29)= .9890
“There is about a 99% chance that the mean of the twelve bottles will exceed 32oz.”
Solution C:
Answer i : H0: µ=24.6 and H1: µ≠24.6 b)
Answer ii: H0: µ=25.4 and H1: µ > 25.4
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please use z table for distribution question
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