Stat Homework

Stat 104 Chapter 5 Name:________________________

5.1 Homework

page 255 #4-8, 11, 17, 19, 21. 23, page 256 #25-29 odd #s, 33, 39, 41, 43, 53, 55, 61, 65, page 257 #73

4. List the three methods for assigning probability.

5. What assumption do we need to make to use the classical method?

6. When can we use the relative frequency method?

7. If we cannot use either the classical method or the relative frequency method, explain how we go about using the subjective method.

8. The experiment is to toss 10 fair coins 25 times each. Which methods can we use to assign probabilities?

11. Is the following a probability model? If not, clearly explain why it is not a probability model.

Gender	Probability
Females	1.1
Males	-0.2

Determine the meaning of the following probabilities:

17. The doctor said the chances of recovery from the surgery were near 100%.

19. The stockbroker said the chances were high that the blue chip stock would gain in value this year.

The experiment is to draw a card at random from a shuffled standard deck of 52 cards. Find the following probabilities:

21. Drawing a jack.

23. Drawing the jack of clubs.

The experiment is to roll a fair die once. Find the following probabilities:

25. Observing a 2.

27. Observing a number greater than 2.

29. Observing a 2 or a 3.

33. The experiment is to toss a fair die two times. The outcomes are observing either a number less than 4 or a number greater than or equal to 4. Construct a tree diagram for the experiment.

Consider the experiment of tossing a fair coin twice.

39. Find the probability of observing zero heads.

41. Find the probability of observing two heads.

Consider the experiment of tossing two fair dice and observing the sum of the two dice. Hint: consider the complete sample space perhaps by creating a tree diagram.

43. What is the probability that the sum of the dice equals 9?

53. Suppose that, in a sample of 100 students who drink hot caffeinated beverages, 35 preferred regular coffee, 20 preferred latte, 20 preferred cappuccino, and 25 preferred tea. Find the probability that a randomly selected student prefers cappuccino.

55. Which method of assigning probability did you use to do the previous problem?

61. Use the following frequency table to estimate the probabilities for each color and construct the probability model. A sample of 100 students was asked to name their favorite color.

Favorite Color	Frequency
Red	25
Blue	25
Green	20
Black	10
Violet	10
Yellow	10

65. The Pew Research Internet Project reported that 14 of the 144 people ages 18-29 that it surveyed would someday like to own a time machine.

a. What is the probability that a randomly chosen 18-29 year old would someday like to own a time machine?

b. What is the probability that a randomly chosen 18-29 year old would not someday like to own a time machine?

c. Which method of assigning probability did you use?

73. Consider the experiment of tossing a fair coin three times and observing either heads or tails. Calculate the probability of exactly two heads.

Stat 104 5.1 HW.docx

Fall 2020 Instructor J Hodgson Page 1 of 2