Question

please explain and show ur work thank you so much

Using the table Opinion on Global Warming Nonissue Serious Concern Total Political Party Democratic 85 415 500 Republican 290 210 500 Independent 70 130 200 Total 445 755 1200

, a) What is the probability that a randomly selected U.S. adult who is a Republican believes that global warming is a serious issue? b) What is the probability that a randomly selected U.S. adult is a Republican given that he or she believes global warming is a serious issue? c) What is P(Serious Concern Democratic)?

Facebook reports that 70% of their users are from outside the United States and that 50% of their users log on to Facebook every day. Suppose that 20% of their users are United States users who log on every day. a) What percentage of Facebook’s users are from the United States? b) What type of probability is the 20% mentioned above? c) Construct a contingency table showing all the joint and marginal probabilities. d) What is the probability that a user is from the United States given that he or she logs on every day? e) Are From United States and Log on Every Day independent? Explain.

Answer 1

1)

	NonIssue	Serious concern	Total
Democratic	85	415	500
Republican	290	210	500
Independent	70	130	200
Total	445	755	1200

(a) The required probability = 210/500 = 0.42

(b) The required probability = 210/755 = 0.278

(c) P(Serious concern Democratic) = 415/1200 = 0.3458

2)

(a) Percentage of Facebook's users who are from the United States = 30%

(b) The probability 20% is a joint probability of a United States user who log on every day

(c)

	Log on every day = Yes	Log on every day = No	Total
United States user = Yes	20%	10%	30%
United States user = No	30%	40%	70%
Total	50%	50%	100%

(d)

The required probability = 0.2/0.5 = 0.4

(e)

No, they are not independent

Since for these two events to be independent, we should have P(United States user = Yes, Log on every day = Yes)

= P(United States user = Yes)*P(Log on every day = Yes)

which does not satisfy in this case