Exam 4: Basic Probability

TABLE 4-1 Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers.A study was recently done that emphasized the problem we all face with drinking and driving.Four hundred accidents that occurred on a Saturday night were analyzed.Two items noted were the number of vehicles involved and whether alcohol played a role in the accident.The numbers are shown below: -Referring to Table 4-1,what proportion of accidents involved more than one vehicle?

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?

True or False: The collection of all the possible events is called a sample space.

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,assume we know the person is a child.The probability that this individual prefers hamburger is ________.

TABLE 4-12 Jake woke up late in the morning on the day that he has to go to school to take an important test.He can either take the shuttle bus which is usually running late 20% of the time or ride his unreliable motorcycle which breaks down 40% of the time.He decides to toss a fair coin to make his choice. -Referring to Table 4-12,if Jake is late to the test,what is the probability that he took the bus?

TABLE 4-12 Jake woke up late in the morning on the day that he has to go to school to take an important test.He can either take the shuttle bus which is usually running late 20% of the time or ride his unreliable motorcycle which breaks down 40% of the time.He decides to toss a fair coin to make his choice. -Referring to Table 4-12,if Jake is late to the test,what is the probability that he rode his bike?

The probability that a new advertising campaign will increase sales is assessed as being 0.80.The probability that the cost of developing the new ad campaign can be kept within the original budget allocation is 0.40.Assuming that the two events are independent,the probability that neither the cost is kept within budget nor the campaign will increase sales is

If the outcome of event A is not affected by event B,then events A and B are said to be

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

TABLE 4-1 Mothers Against Drunk Driving is a very visible group whose main focus is to educate the public about the harm caused by drunk drivers.A study was recently done that emphasized the problem we all face with drinking and driving.Four hundred accidents that occurred on a Saturday night were analyzed.Two items noted were the number of vehicles involved and whether alcohol played a role in the accident.The numbers are shown below: -Referring to Table 4-1,what proportion of accidents involved alcohol and a single vehicle?

True or False: If P(A)= 0.4 and P(B)= 0.6,then A and B must be collectively exhaustive.

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 did well on the midterm or went bar hopping the weekend before the midterm?

The probability that house sales will increase in the next 6 months is estimated to be 0.25.The probability that the interest rates on housing loans will go up in the same period is estimated to be 0.74.The probability that house sales or interest rates will go up during the next 6 months is estimated to be 0.89.The events increase in house sales and no increase in house sales in the next 6 months are

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 annual household income is over $50,000 if the residents of a household own 2 cars is

TABLE 4-7 The next state lottery will have the following payoffs possible with their associated probabilities. You buy a single ticket. -Referring to Table 4-7,the probability that you win any money is ________.

A survey of banks revealed the following distribution for the interest rate being charged on a home loan (based on a 30-year mortgage with a 10% down payment). If a bank is selected at random from this distribution,what is the chance that the interest rate charged on a home loan will exceed 3.49%?

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 or is white and has claimed bias?

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 4-6 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,if a randomly selected student has not passed the ELM,the probability that the student is from southern Texas 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 B,the probability that it is properly sealed is ________.