Exam 4: Basic Probability

If events A and B are mutually exclusive and collectively exhaustive,what is the probability that event A occurs?

If event A and event B cannot occur at the same time,then events A and B are said to be

All the events in the sample space that are not part of the specified event are called

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

True or False: An investment consultant is recommending a certain class of mutual funds to the clienteles based on its exceptionally high probability of gain.It is an unethical practice not to also recommend a class of mutual funds with an exceptionally high probability of loss.

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 increase in interest rates in the next 6 months are

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 the cost is not kept within budget or the campaign will not increase sales is

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 and prefers chicken is ________.

True or False: To ethically advertise a school lottery scheme to try to raise money for the athletic department,the organizer of the lottery does not need to explicitly specify the probability of each of the prizes in the lottery.

If two events are mutually exclusive and collectively exhaustive,what is the probability that both occur?

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 ________.

The employees of a company were surveyed on questions regarding their educational background (college degree or no college degree)and marital status (single or married).Of the 600 employees,400 had college degrees,100 were single,and 60 were single college graduates.The probability that an employee of the company does not have a college degree is

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 that the patron is a male is ________.

TABLE 4-9 A survey conducted by the Segal Company of New York found that in a sample of 189 large companies,40 offered stock options to their board members as part of their noncash compensation packages.For small- to mid-sized companies,43 of the 180 surveyed indicated that they offer stock options as part of their noncash compensation packages to their board members. -Referring to Table 4-9,if a randomly selected company offered stock options to their board members,what is the probability that it is a large company?

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 someone from northern Texas who has not passed the ELM is ________.

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 is ________.

The closing price of a company's stock tomorrow can be lower,higher or the same as today's closing price.Without any prior information that may affect the price of the stock tomorrow,the probability that it will close higher than today's close is .This is an example of using which of the following probability approaches?

When using the general multiplication rule,P(A and B.is equal to

TABLE 4-8 According to the record of the registrar's office at a state university,35% of the students are freshman,25% are sophomore,16% are junior and the rest are senior.Among the freshmen,sophomores,juniors and seniors,the portion of students who live in the dormitory are,respectively,80%,60%,30% and 20%. -Referring to Table 4-8,what is the probability that a randomly selected student is a junior or senior who lives in a dormitory?

True or False: If P(A and B)= 0,then A and B must be collectively exhaustive.