Exam 6: Probability

Tea and Seltzer Suppose 55 percent of adults drink tea,45 percent drink seltzer,and 10 percent drink both. -{Tea and Seltzer Narrative} What is the probability that a randomly chosen adult doesn't drink tea or seltzer?

If P(B)= .7 and P(B|A)= .4,then P(A and B)must be .28.

Which of the following statements is false regarding a scenario using Bayes' Law?

Cysts After researching cysts of a particular type,a doctor learns that out of 10,000 such cysts examined,1,500 are malignant and 8,500 are benign.A diagnostic test is available which is accurate 80% of the time (whether the cyst is malignant or not).The doctor has discovered the same type of cyst in a patient. -{Cysts Narrative} What is the probability that the patient will test negative?

Drunk Drivers Six 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: Number of Vehieles Involved Did aloholplay a role? 1 2 3 Totals Yes 75 125 50 250 Na 50 225 75 350 Totals 125 350 125 600 -{Drunk Drivers Narrative} If alcohol was not involved,what proportion of the accidents were single vehicle?

If two events are independent,what is the probability that they both occur?

Which of the following is a requirement of the probabilities assigned to outcome O_i?

A conditional probability of A given B is written in probability notation as ____________________.

Hobby Shop Sales Sales records of a hobby shop showed the following number of radio controlled trucks sold weekly for each of the last 50 weeks. Number of Trucks Sald Number af Weeks 0 20 1 15 2 10 3 4 4 1 -{Hobby Shop Sales Narrative} Define the random experiment of interest to the store.

If events A and B are independent then:

An individual outcome of a sample space is called a(n)____________________ event.

In the scenario of Bayes' Law,P(A|B)is a posterior probability,while P(B|A)is a(n)____________________ probability.

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

If either event A or event B must occur,then A and B are mutually exclusive and collectively exhaustive events.

Condo Sales and Interest Rates The probability that condo sales will increase in the next 6 months is estimated to be 0.30.The probability that the interest rates on condo loans will go up in the same period is estimated to be 0.75.The probability that condo sales or interest rates will go up during the next 6 months is estimated to be 0.90. -Suppose we have two events A and B.We can apply the addition rule to compute the probability that at least one of these events occurs.

Condo Sales and Interest Rates The probability that condo sales will increase in the next 6 months is estimated to be 0.30.The probability that the interest rates on condo loans will go up in the same period is estimated to be 0.75.The probability that condo sales or interest rates will go up during the next 6 months is estimated to be 0.90. -Posterior probabilities can be calculated using the addition rule for mutually exclusive events.

When A and B are mutually exclusive,P(A or B)can be found by adding P(A)and P(B).

The ____________________ of two events A and B is the event that occurs when either A or B or both occur.

Sports Fans Suppose that past history shows that 5% of college students are sports fans.A sample of 10 students is to be selected. -Predicting the outcome of a football game is using the subjective approach to probability.

If the events A and B are independent with P(A)= 0.35 and P(B)= 0.45,then the probability that both events will occur simultaneously is: