Exam 4: Basic Probability

TABLE 4-3 A survey is taken among customers of a fast-food restaurant to determine preference for hamburger or chicken.Of 200 respondents selected,75 were children and 125 were adults.120 preferred hamburger and 80 preferred chicken.55 of the children preferred hamburger. -Referring to Table 4-3,the probability that a randomly selected individual is an adult or a child is ________.

According to a survey of American households,the probability that the residents own 2 cars if annual household income is over $50,000 is 80%.Of the households surveyed,60% had incomes over $50,000 and 70% had 2 cars.The probability that the residents do not own 2 cars if annual household income is not over $50,000 is

When A and B are mutually exclusive,P(A or B)can be found by adding P(A)and P(B).

A company has 2 machines that produce widgets.An older machine produces 23% defective widgets,while the new machine produces only 8% defective widgets.In addition,the new machine produces 3 times as many widgets as the older machine does.Given that a widget was produced by the new machine,what is the probability it is not defective?

TABLE 4-6 At a Texas college,60% of the students are from the southern part of the state,30% are from the northern part of the state,and the remaining 10% are from out-of-state.All students must take and pass an Entry Level Math (ELM)test.60% of the southerners have passed the ELM,70% of the northerners have passed the ELM,and 90% of the out-of-staters have passed the ELM. -Referring to Table 4-6,the probability that a randomly selected student is not from southern Texas and has not passed the ELM is ________.

A high school debate team of 4 is to be chosen from a class of 35.How many possible ways can the team be formed?

TABLE 4-10 Are whites more likely to claim bias? It was found that 60% of the workers were white,30% were black and 10% are other races.Given that a worker was white,the probability that the worker had claimed bias was 30%.Given that a worker was black,the probability that the worker had claimed bias was 40%.Given that a worker was other race,the probability that the worker had claimed bias was 0%. -Referring to Table 4-10,what is the probability that a randomly selected worker is black and had not claimed bias?

According to a survey of American households,the probability that the residents own 2 cars if annual household income is over $50,000 is 80%.Of the households surveyed,60% had incomes over $50,000 and 70% had 2 cars.The probability that the residents of a household own 2 cars and have an income over $50,000 a year is

TABLE 4-5 In a meat packaging plant,Machine A accounts for 60% of the plant's output,while Machine B accounts for 40% of the plant's output.In total,4% of the packages are improperly sealed.Also,3% of the packages are from Machine A and are improperly sealed. -Referring to Table 4-5,if a package is selected at random,the probability that it will be properly sealed is ________.

TABLE 4-5 In a meat packaging plant,Machine A accounts for 60% of the plant's output,while Machine B accounts for 40% of the plant's output.In total,4% of the packages are improperly sealed.Also,3% of the packages are from Machine A and are improperly sealed. -Referring to Table 4-5,if a package selected at random came from Machine A,the probability that it is improperly sealed is ________.

Suppose A and B are mutually exclusive events where P(A)= 0.4 and P(B)= 0.5.Then P(A or B)= ________.

TABLE 4-2 An alcohol awareness task force at a Big-Ten university sampled 200 students after the midterm to ask them whether they went bar hopping the weekend before the midterm or spent the weekend studying,and whether they did well or poorly on the midterm.The following result was obtained. -Referring to Table 4-2,what is the probability that a randomly selected student who went bar hopping did well on the midterm?

Selection of raffle tickets from a large bowl is an example of

If A and B cannot occur at the same time they are called mutually exclusive.

If two events are collectively exhaustive,what is the probability that both occur at the same time?

Suppose A and B are events where P(A)= 0.4,P(B)= 0.5,and P(A and B)= 0.1.Then P(B|A)= ________.

TABLE 4-4 Suppose that patrons of a restaurant were asked whether they preferred water or whether they preferred soda.70% said that they preferred water.60% of the patrons were male.80% of the males preferred water. -Referring to Table 4-4,suppose a randomly selected patron prefers water.Then the probability the patron is a male is ________.

At the International Pancakes Hut,there are 4 different ways to have an egg cooked,7 different choices of pancakes,5 different types of syrups and 8 different beverages.How many different ways are there to order an egg,a pancake with a choice of syrup and a beverage?

The collection of all the possible events is called a sample space.

TABLE 4-4 Suppose that patrons of a restaurant were asked whether they preferred water or whether they preferred soda.70% said that they preferred water.60% of the patrons were male.80% of the males preferred water. -Referring to Table 4-4,suppose a randomly selected patron prefers soda.Then the probability the patron is a male is ________.