Exam 6: Probability

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. -We can apply the multiplication rule to compute the probability that two events occur at the same time.

If A and B are independent,then P(A|B)= ____________________.

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. -Prior probability is also called likelihood probability.

Construction Bids A construction company has submitted bids on two separate state contracts,A and B.The company feels that it has a 60% chance of winning contract A,and a 50% chance of winning contract B.Furthermore,the company believes that it has an 80% chance of winning contract A if it wins contract B. -{Construction Bids Narrative} If the company wins contract B,what is the probability that it will not win contract A?

A random experiment is an action or process that leads to one of several possible ____________________.

GPA and Class A college professor classifies his students according to their grade point average (GPA)and their class rank.GPA is on a 0.0-4.0 scale,and class rank is defined as the under class (freshmen and sophomores)and the upper class (juniors and seniors).One student is selected at random. $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ GPA Class Under 2.0 2.0 - 3. 0 Over 3.0 Under 0.05 0.25 0.10 Upper 0.10 0.30 0.20 -{GPA and Class Narrative} What is the probability that the student is in the lower class?

GPA and Class A college professor classifies his students according to their grade point average (GPA)and their class rank.GPA is on a 0.0-4.0 scale,and class rank is defined as the under class (freshmen and sophomores)and the upper class (juniors and seniors).One student is selected at random. $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ GPA Class Under 2.0 2.0 - 3. 0 Over 3.0 Under 0.05 0.25 0.10 Upper 0.10 0.30 0.20 -{GPA and Class Narrative} What is the probability that the student has GPA over 3.0?

Which of the following statements is false?

Messenger Service Three messenger services deliver to a small town in Oregon.Service A has 60% of all the scheduled deliveries,service B has 30%,and service C has the remaining 10%.Their on-time rates are 80%,60%,and 40% respectively.Define event O as a service delivers a package on time. -{Messenger Service Narrative} If a package was delivered on time,what is the probability that it was service A?

Marital Status An insurance company has collected the following data on the gender and marital status of 570 customers. Marital Status Gender Single Married Divorced Male 50 250 30 Female 100 100 40 Suppose that a customer is selected at random. -{Marital Status Narrative} Find the probability that the customer selected is a married female.

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

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} What is the probability of selling between 1 and 3 (inclusive)trucks in any given week?

The outcomes of a sample space must be ____________________,which means that all possible outcomes must be included.

Equity Loan Rates A survey of banks estimated the following probabilities for the interest rate being charged on a equity loan based on a 30-year loan,based on past records. Interest Rate 0.0\% 6.5\% 7.0\% 7.5\% >7.5\% Probability 0.20 0.23 0.25 0.28 .04 -Two or more events are said to be independent when the occurrence of one event has no effect on the probability that another will occur.

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

Messenger Service Three messenger services deliver to a small town in Oregon.Service A has 60% of all the scheduled deliveries,service B has 30%,and service C has the remaining 10%.Their on-time rates are 80%,60%,and 40% respectively.Define event O as a service delivers a package on time. -{Messenger Service Narrative} If a package was delivered 40 minutes late,what is the probability that it was service A?

Cars Suppose X = the number of cars owned by a family in the U.S.The probability distribution of X is shown in the table below. X 0 1 2 3 Probability 0.56 0.23 0.12 0.09 -{Cars Narrative} Suppose you choose two families at random.What is the chance that they each own one car? (That means family A owns a car and family B owns a car. )

Certification Test A standard certification test was given at three locations.1,000 candidates took the test at location A,600 candidates at location B,and 400 candidates at location C.The percentages of candidates from locations A,B,and C who passed the test were 70%,68%,and 77%,respectively.One candidate is selected at random from among those who took the test. -{Certification Test Narrative} What is the probability that the selected candidate passed the test?

GPA and Class A college professor classifies his students according to their grade point average (GPA)and their class rank.GPA is on a 0.0-4.0 scale,and class rank is defined as the under class (freshmen and sophomores)and the upper class (juniors and seniors).One student is selected at random. $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ $\quad$ GPA Class Under 2.0 2.0 - 3. 0 Over 3.0 Under 0.05 0.25 0.10 Upper 0.10 0.30 0.20 -{GPA and Class Narrative} What is the probability that the student is in the upper class?

Suppose two events A and B are related.The ____________________ probability of A is the probability that A occurs,regardless of whether event B occurred or not.