Exam 2: Probability Concepts and Applications

A southwestern tourist city has records indicating that the average daily temperature in the summer is 82 degrees F,which is normally distributed with a standard deviation of 3 degrees F.Based on these records,determine: (a)the probability of a daily temperature between 79 degrees F and 85 degrees F. (b)the probability that the daily temperature exceeds 90 degrees F. (c)the probability that the daily temperature is below 76 degrees F.

If we roll a single die twice,the probability that the sum of the dots showing on the two rolls equals four (4),is 1/6.

In what way is the F distribution often used?

A probability is a numerical statement about the chance that an event will occur.

Explain what a discrete random variable is.

Using the table for finding the areas under normal curves,find the area under a normal curve with a mean of 200 and a standard deviation of 10 between the values of: (a)200 to 205. (b)195 to 205. (c)200 to 215. (d)195 to 215. (e)186.5 to 217.

A company is considering producing some new Gameboy electronic games.Based on past records,management believes that there is a 70 percent chance that each of these will be successful and a 30 percent chance of failure.Market research may be used to revise these probabilities.In the past,the successful products were predicted to be successful based on market research 90 percent of the time.However,for products that failed,the market research predicted these would be successes 20 percent of the time.If market research is performed for a new product,what is the probability that the results indicate an unsuccessful market for the product and the product is actually unsuccessful?

If two events (A,B)are not mutually exclusive,what is the probability of event A or event B occurring?

At a university with 1,000 business majors,there are 200 business students enrolled in an introductory statistics course.Of these 200 students,50 are also enrolled in an introductory accounting course.There are an additional 250 business students enrolled in accounting but not enrolled in statistics.If a business student is selected at random,what is the probability that the student is enrolled in both statistics and accounting?

Bayes' theorem enables us to calculate the probability that one event takes place knowing that a second event has or has not taken place.

A dry cleaning business offers a pick-up and delivery service for a 10 percent surcharge.Management believes 60 percent of the existing customers will take advantage of this service.They are also considering offering customers the option of opening an account and receiving monthly bills.They believe 60 percent of customers (regardless of whether or not they use the pick-up service)will use the account service.If the two services are introduced to the market,what is the probability that a customer uses only one of these services?

Which of the following characteristics is true for a normal probability distribution?

Using a standard deck of 52 cards,explain why the situation of drawing a 7 and a club is not collectively exhaustive.

A consulting firm has received 2 Super Bowl playoff tickets from one of its clients.To be fair,the firm is randomly selecting two different employee names to "win" the tickets.There are 6 secretaries,5 consultants,and 4 partners in the firm.Which of the following statements is true?

A posterior probability is a revised probability.

The time required to complete a project is known to be normally distributed with a mean of 44 weeks and a standard deviation of 8 weeks. (a)What is the probability that the project is finished in 40 weeks or fewer? (b)What is the probability that the project is finished in 52 weeks or fewer? (c)There is a 95 percent chance that the project will be finished in fewer than how many weeks?

Historical data indicates that only 20% of cable customers are willing to switch companies.If a binomial process is assumed,then in a sample of 20 cable customers,what is the probability that no more than 3 customers would be willing to switch their cable?

Data for a particular subdivision near downtown Houston indicate that the average price per square foot for a home is $100 with a standard deviation of $5 (normally distributed).What is the probability that the average price per square foot for a home is greater than $90?

Data for a particular subdivision near downtown Houston indicate that the average price per square foot for a home is $100 with a standard deviation of $5 (normally distributed).What is the probability that the average price per square foot for a home is less than $108?

The number of bad checks written at a local store is an example of a discrete random variable.