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Answer:
We know that:
1/5 = 0.2 of all adults in US have type O blood.
Then: 4/5 = 0.8 of all adults in US do not have type O blood.
a) All four are type O.
Let's think this, as four events with two possible outcomes, having type O blood, with a probability of 0.2, and not having type O blood with a probability of 0.8
Now if we want the four people to have type O blood, then we have the outcome with probability 0.2 four times, and as we know, the joint probability is equal to the product of the individual probabilities:
P =0.2^4 = 0.0016
b) None of them is type O.
Similar to the above case, but this time we work with four times the probability 0.8
P = 0.8^4 = 04096
c) Two of the four are type O.
Here we will have two times the probability 0.2, and two times the probability 0.8.
p = 0.2^2*0.8^2
But, if the people is ordered, the two persons with type O blood can be:
first and second
first and third
first and fourth.
second and third
second and fourth
third and fourth.
6 different combinations, then the actual probability for this case will be:
P = 6*p = 6*(0.2^2*0.8^2) = 0.1536
The probability of All four are type O, None of them is type O, and Two out of the four are type O is 0.0016, 0.4096, and 0.0256 respectively.
What is probability?
Probability means possibility. It deals with the occurrence of a random event. The value of probability can only be from 0 to 1. Its basic meaning is something is likely to happen. It is the ratio of the favorable event to the total number of events.
About 1/5 of all adults in the United States have type O blood.
p = 0.2
q = 1 - p = 1 - 0.2 = 0.8
a. All four are type O. The probability will be
P = p⁴
P = 0.2⁴
P = 0.0016
b. None of them is type O. The probability will be
P = q⁴
P = 0.8⁴
P = 0.4096
c. Two out of the four are type O. The probability will be
P = p² × q²
P = 0.2² × 0.8²
P = 0.04 × 0.64
P = 0.0256
More about the probability link is given below.
https://brainly.com/question/795909
