Kevin recorded the ages of the next 12 people who entered his grocery store. He asked his brother John to find the mean, median,
1 answer:
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Answer:
a) 0.984
b) 20 people
Step-by-step explanation:
a)
If The probability that a person carries the gene is 0.1, then in a sample of 20 people, 2 should carry the gene.
Now, we want to know how many samples there are with this property.
Since we have 20 elements where 18 are alike (do not carry the gene) and 2 are alike (carry the gene), we have to compute the number of permutations of 20 elements in which 18 are alike and 2 are alike. This number is
In this 190 20-tuples there are only 3 where the 2 carriers of the gene are in the first 3 places, namely
(1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)
(1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)
(0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)
where 1=carries the gene, 0=does not carry the gene.
So there are 190-3 = 187 elements in which the first 3 elements have no 2 carriers, hence the probability that 4 or more people will have to be tested until 2 of them with the gene are detected is 187/190 = 0.984 (98.4%) rounded to three decimal places.
b)
Given that the probability that a person carries the gene is 0.1, then in a sample of 20 people, 20*0.1 = 2 should carry the gene.
The answer is 8
Here's why:
The exponents are subtracted one from another when divided.
We can look at the problem this way:
Since we have the power of -1 on the 3, we apply this rule:
Also this rule because we have the power of 1 on the 6:
Then we get this:
We apply the rule:
We get this:
Here's why:
The exponents are subtracted one from another when divided.
We can look at the problem this way:
Since we have the power of -1 on the 3, we apply this rule:
Also this rule because we have the power of 1 on the 6:
Then we get this:
We apply the rule:
We get this:
Answer:
last option at the bottom
Step-by-step explanation:
(see attached)
