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At Least One. In Exercises 5鈥�12, find the probability.

Three Girls Find the probability that when a couple has three children, at least one of them is a girl. (Assume that boys and girls are equally likely.)

In Exercises 1鈥�10, use the data in the accompanying table and express all results in decimal form. (The data are from 鈥淢ortality Reduction with Air Bag and Seat Belt Use in Head-On Passenger Car Collisions,鈥� by Crandall, Olson, and Sklar, American Journal of Epidemiology, Vol. 153, No. 3.) Drivers Involved in Head-On Collision of Passenger Cars.

Drivers Involved in Head-On Collision of Passenger Cars

No Seatbelt or Driver Not Killed If one of the drivers is randomly selected, find the probability of getting someone who did not use a seatbelt or was not killed

Subjective Probability Estimate the probability that the next time you ride in a car, the car gets a flat tire.

In Exercises 5鈥�36, express allprobabilitiesas fractions.

ATM Pin Numbers A thief steals an ATM card and must randomly guess the correct pin code that consists of four digits (each 0 through 9) that must be entered in the correct order. Repetition of digits is allowed. What is the probability of a correct guess on the first try?

In Exercises 5鈥�36, express all probabilities as fractions.

Social Security Numbers A Social Security number consists of nine digits in a particular order, and repetition of digits is allowed. After seeing the last four digits printed on a receipt, if you randomly select the other digits, what is the probability of getting the correct Social Security number of the person who was given the receipt?

Penicillin 鈥淲ho discovered penicillin: Sean Penn, William Penn, Penn Jillette, Alexander Fleming, or Louis Pasteur?鈥� If you make a random guess for the answer to that question, what is the probability that your answer is the correct answer of Alexander Fleming?

Critical Thinking: Interpreting results from a test for smoking

It is estimated that roughly half of smokers lie when asked about their smoking involvement. Pulse Co-Oximeters may be a way to get information about smoking without relying on patients鈥� statements. Pulse CO-oximeters use light that shines through a fingernail, and it measures carbon monoxide in blood. These devices are used by firemen and emergency departments to detect carbon monoxide poisoning, but they can also be used to identify smokers. The accompanying table lists results from people aged 18鈥�44 when the pulse CO-oximeters is set to detect a 6% or higher level of carboxyhemoglobin (based on data from 鈥淐arbon Monoxide Test Can Be Used to Identify Smoker,鈥� by Patrice Wendling, Internal Medicine News, Vol. 40., No. 1, and Centers for Disease Control and Prevention).

CO-Oximetry Test for Smoking

SpecificityFind the specificity of the test by finding the probability of a true negative, given that the subject does not smoke.

In Exercises 6鈥�10, use the following results from tests of an experiment to test the effectiveness of an experimental vaccine for children (based on data from USA Today). Express all probabilities in decimal form.

If 1 of the 1602 subjects is randomly selected, find the probability of getting 1 that developed flu.

New Lottery Game In the Monopoly Millionaires鈥� Club lottery game, you pay $5 and select five different numbers between 1 and 52, and then a sixth number between 1 and 28 is randomly assigned to you. Winning requires that your five numbers match those drawn (in any order), and then your sixth assigned number must also match.

a. What is the probability of selecting the correct five numbers between 1 and 52?

b. What is the probability of getting the correct sixth number that is assigned to you?

c. What is the probability of selecting the correct five numbers and getting the correct sixth number?

Finding Complements. In Exercises 5鈥�8, find the indicated complements.

Flights According to the Bureau of Transportation, 80.3% of American Airlines flights arrive on time. What is the probability of randomly selecting an American Airlines flight that does not arrive on time?