Exam 4: Probability

What important question must you answer before computing an "or" probability? How does the answer influence your computation?

When 100 engines are shipped, all of them are free of defects. Select a written description of the complement of the given event.

If you drew one card from a standard deck, would it be "significant" to draw a 5? Answer the question, considering an event to be "significant" if its probability is less than or equal to 0.05.

In a recent year, 304 of the approximately 300,000,000 people in the United States were struck by lightning. The probability that a randomly selected person in the United States will be struck by lightning this year is 0.00000101. Is a golfer reasoning correctly if he or she is caught out in a thunderstorm and does not seek shelter from lightening because the probability of being struck is so small?

Some employers use lie detector tests to screen job applicants. Lie detector tests are not completely reliable. Suppose that in a lie detector test, 65% of lies are identified as lies and That 14% of true statements are also identified as lies. A company gives its job applicants a Polygraph test, asking "Did you tell the truth on your job application?". Suppose that 93% of The job applicants tell the truth during the polygraph test. What is the probability that a person Who fails the test was actually telling the truth?

Select the correct interpretation of the probability of guessing the date of his birth, given that he told you in what month he was born. Interpret an event as significant if its probability is Less than or equal to 0.05.

Determine whether the events are disjoint. Read a book by Mark Twain. Read about Tom Sawyer.

Suppose you are playing a game of chance. If you bet $5 on a certain event, you will collect $115 (including your $5 bet)if you win. Find the odds used for determining the payoff.

Discuss the advantages and disadvantages of odds.

A multiple choice question has 18 possible answers, only one of which is correct. "significant" to answer a question correctly if a random guess is made? Consider an event to Be "significant" if its probability is less than or equal to 0.05.

Evaluate the expression ${ } _ { 8 } P _ { 4 }$ .

Fred and Ed each have a bag of candy containing a lemon drop (LD), a cherry drop(CD), and a lollipop (LP). Each takes out a piece from their own bag and eats it. What are the possible Pairs of candies eaten?

The probability of a randomly selected car crashing during a year is 0.0423 (based on data from the Statistical Abstract of the United States). If a family has three cars, find the probability that at least one of them has a crash during the year. Is there any reason why this probability might be wrong?

Use technology to develop a simulation of the given problem (100 trials). simulation, then estimate the probability based on its results. The probability that when 75 people are surveyed, at least five of them have the same birth date. (Ignore leap years.)

Some employers use lie detector tests to screen job applicants. Lie detector tests are not completely reliable. Suppose that in a lie detector test, 65% of lies are identified as lies and That 14% of true statements are also identified as lies. A company gives its job applicants a Polygraph test, asking "Did you tell the truth on your job application?" Suppose that 93% of The job applicants tell the truth during the polygraph test. What is the probability that a person Who fails the test was actually telling the truth?

The table below shows the soft drinks preferences of pepole in three age groups. Cola Root Beer Lemon-lime Under 21 years of age 40 25 20 Between 21 and 40 35 20 30 Over 40 years of age 20 30 35 If one of the 255 subjects is randomly selected, find the probability that the person drinks root beer given that they are over 40 .

In a certain town, 10% of people commute to work by bicycle. If a person is selected randomly from the town, what are the odds against selecting someone who commutes by Bicycle?

On an exam on probability concepts, Sue had an answer of $\frac { 13 } { 8 }$ for one problem. Explain how she knew that this result was incorrect.

Refer to the table which summarizes the results of testing for a certain disease. Positive Test Result Negative Test Result Subject has the disease Subject does not have the disease 111 4 11 172 If one of the results is randomly selected, what is the probability that it is a false negative (test indicates the person does not have the disease when in fact they do)? What does this Probability suggest about the accuracy of the test?

Refer to the table which summarizes the results of testing for a certain disease. Positive Test Result Negative Test Result Subject has the disease 87 9 Subject does not have the disease 27 312 A test subject is randomly selected and tested for the disease. What is the probability the subject has the disease given that the test result is negative.