Answer:
[tex]P(x \geq 6)=P(X=6)+P(X=7)[/tex]
And we can find the individual probabilities:
[tex]P(X=6)=(7C6)(0.91)^6 (1-0.91)^{7-6}=0.358[/tex]
[tex]P(X=7)=(7C7)(0.91)^7 (1-0.91)^{7-7}=0.517[/tex]
And replacing we got:
[tex]P(x \geq 6)=P(X=6)+P(X=7)= 0.358+0.517=0.875[/tex]
Step-by-step explanation:
Previous concepts
The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".
Solution to the problem
Let X the random variable of interest, on this case we now that:
[tex]X \sim Binom(n=7, p=1-0.09=0.91)[/tex]
The probability associated to a failure would be p =1-0.09 = 0.91
The probability mass function for the Binomial distribution is given as:
[tex]P(X)=(nCx)(p)^x (1-p)^{n-x}[/tex]
Where (nCx) means combinatory and it's given by this formula:
[tex]nCx=\frac{n!}{(n-x)! x!}[/tex]
And we want to find this probability:
[tex]P(x \geq 6)=P(X=6)+P(X=7)[/tex]
And we can find the individual probabilities:
[tex]P(X=6)=(7C6)(0.91)^6 (1-0.91)^{7-6}=0.358[/tex]
[tex]P(X=7)=(7C7)(0.91)^7 (1-0.91)^{7-7}=0.517[/tex]
And replacing we got:
[tex]P(x \geq 6)=P(X=6)+P(X=7)= 0.358+0.517=0.875[/tex]
The probability of at least 6 failures in 7 trials of the binomial experiment is 0%
A binomial probability is represented as:
[tex]P(x) = ^nC_x * p^x * (1 -p)^{n-x}[/tex]
From the question, we have:
n = 7
x >= 6
So, we have:
[tex]P(x \ge 6) = P(6) + P(7)[/tex]
This gives
[tex]P(x \ge 6) = ^7C_6 * (9\%)^6 * (1 -9\%)^{7-6} +^7C_7 * (9\%)^7 * (1 -9\%)^{7-7}[/tex]
Solve
[tex]P(x \ge 6) =0.00000343311[/tex]
Express as percentage
[tex]P(x \ge 6) =0.000343311\%[/tex]
Approximate
[tex]P(x \ge 6) =0\%[/tex]
Hence, the probability of at least 6 failures is 0%
Read more about probability at:
https://brainly.com/question/25870256
