Binomial
Binomial distribution can be used because the situation satisfies all the following conditions:1. Number of trials is known and remains constant (n=10)2. Each trial is Bernoulli (i.e. exactly two possible outcomes) (defective/normal)3. Probability is known and remains constant throughout the trials (p=5%)4. All trials are random and independent of the others (assumed from context)The number of successes, x, is then given by[tex]P(x)=C(n,x)p^x(1-p)^{n-x}[/tex]where[tex]C(n,x)=\frac{n!}{x!(n-x)!}[/tex]
Substituting values, p=0.05, n=10, X=exactly 1
for X=1 (defective out of n)
P(X=1)=C(10,1)0.05^1*(1-0.05)^(10-1)
=10!/(1!9!)*0.05*0.95^9
=10*0.05*0.0630249
=0.315125 (to 6 places of decimal)
