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1. I flip a coin twice and count the number of heads. Which is a valid assignmen

ID: 3349908 • Letter: 1

Question

1. I flip a coin twice and count the number of heads. Which is a valid assignment of probabilities for the number of heads observed in two flips?

c. All of the answer choices are correct.

2.    A randomly selected sample of 100 horse owners found that 72 of them feed two flakes of grass hay in the morning and one flake of alfalfa plus one flake of grass hay in the evening to their horses while the rest feed two flakes of grass hay in the morning and one flake of alfalfa plus oat hay in the evening. The estimated probability that horse owners feed grass hay in the A.M. and alfalfa plus oat hay in the P.M. is:
      

a. 0.50.
b.. 0.28.
c. 0.75.

3. According to the Current Population Survey, the following table summarizes probabilities for randomly selecting a full-time student in various age groups:

Age

15–17

18–24

25–34

35 or older older

Probability

0.007

0.573

0.260

0.160

If we randomly select a full-time student, what is the probability that he/she is 25 or older?

a. 0.260

b. 0.420

c. The answer is impossible to determine from the information given

Numher of heads Probability

Explanation / Answer

Question 1:

For the probability distribution to be valid, each of the probability value must lie from 0 to 1 and the sum of all probabilities should be equal to 1. This is followed in both the given probability distributions

Therefore C) all answers are correct is the correct answer here.

Question 2:

Out of 100 horse owners, 72 feed on two flakes of grass hay in the morning, one flake of alfalfa plus one flake of grass hay in the evening

Therefore 28 of them would feed on two flakes of grass hay in the morning and one flake of alfalfa plus oat hay in the evening, therefore the required probability here is computed as:

= 28/100 = 0.28

Therefore 0.28 is the required probability here.

Question 3:

Probability that the student is 25 or older is computed here as:

= 0.260 + 0.160

= 0.420

Therefore 0.420 is the required probability here.