http://davidmlane.com/hyperstat/z_table.html
BUT out of how many cameras made? 18 out of what = what?
On a production line making cameras, the probability of a randomly chosen camera being substandard is 0.072. Find the probability that there are fewer than 18 cameras which are substandard.
2 answers
p=0.072(p is the probability of success)
n=300 ( n is the no. of times an exp. is performed)
q=1-0.072 ;q=0.928 (q is the probability of failure)
mean=μ=np ; μ=300x0.072 ; μ=21.6
σ^2=npq ; = 300x0.072x0.928 ; σ^2=20.0448
σ=4.477
p(x<18)=p(x<17.5) (continuity error is applied which is 0.5)
now we will standardize it
p(x<17.5-21.6/4.477) ; p(x<-0.9157)
1- (standard area of the graph 0.9157)
=1-8199
=0.180
n=300 ( n is the no. of times an exp. is performed)
q=1-0.072 ;q=0.928 (q is the probability of failure)
mean=μ=np ; μ=300x0.072 ; μ=21.6
σ^2=npq ; = 300x0.072x0.928 ; σ^2=20.0448
σ=4.477
p(x<18)=p(x<17.5) (continuity error is applied which is 0.5)
now we will standardize it
p(x<17.5-21.6/4.477) ; p(x<-0.9157)
1- (standard area of the graph 0.9157)
=1-8199
=0.180
1 answer