Answer :
Answer:
x P(x)
0 0.4167
1 0.5
2 0.0833
3 0
Step-by-step explanation:
The speedometers are chosen without replacement, which means that the hypergeometric distribution is used to solve this question.
Hypergeometric distribution:
The probability of x successes is given by the following formula:
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
In which:
x is the number of successes.
N is the size of the population.
n is the size of the sample.
k is the total number of desired outcomes.
In this question:
7 + 2 = 9 speedometers, which means that [tex]N = 9[/tex]
2 are not correctly calibrated, which means that [tex]k = 2[/tex]
3 are chosen, which means that [tex]n = 3[/tex]
Complete the probability distribution table.
Probability of each outcome.
So
[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]
[tex]P(X = 0) = h(0,9,3,2) = \frac{C_{2,0}*C_{7,3}}{C_{9,3}} = 0.4167[/tex]
[tex]P(X = 1) = h(1,9,3,2) = \frac{C_{2,1}*C_{7,2}}{C_{9,3}} = 0.5[/tex]
[tex]P(X = 2) = h(2,9,3,2) = \frac{C_{2,2}*C_{7,1}}{C_{9,3}} = 0.0833[/tex]
Only 2 defective, so [tex]P(X = 3) = 0[/tex]
Probability distribution table:
x P(x)
0 0.4167
1 0.5
2 0.0833
3 0