asu ecn 221 exam 1 study guide

the union of events A and B is the event containing ___________.

all the sample points belonging to A or B or both

the sum of deviations of the individual data elements from their mean is_____.

always equal to zero

classical probability

assigning probabilities based on assumption of equally likely outcomes

relative probability

assigning probabilities based on experimentation or historical data

subjective probability

assigning probabilities based on judgment

the value of the sum of the squared deviations form the mean, i.e., summation(x-xbar)^2 must always be______.

at least zero

two events with nonzero probabilities_________.

cannot be both mutually exclusive and independent

event probability

collection of sample points

experimental outcomes that are based on measurement scales such as time, weight, and distance can be described by ___________________ random variables

continuous

highway patrol officers measure the speed of automobiles on a highway using radar equipment. the random variable in this experiment is speed, measured in mph. this random variable is a _____________.

continuous random variable

qualititative

gender, marital status

covariance

indicated the direction of a linear relationship between two variables -positive is positive -negative is negative

a sample point refers to a(n)__________.

individual outcome of an experiment

sample point measures_______.

individual outcome of experiment

which of the following is a measure of dispersion?

interquartile range

the expected value of a discrete random variable___________.

is the average value for the random variable over many repeats of the experiment

range

max-min

correlation

measure of linear association

variance

measures how far data is spread out

the probability of the intersection of two mutually exclusive events___________.

must always be equal to 0

the probability of no breakdowns in a month is____________. # of breakdowns probability 0 .12 1 .38 2 .25 3 .18 4 .07

none of the answers is correct

which of the following is(are) required condition(s) for a discrete probability function?

none of the following

quantitative

numeric values

the interquartile range is_________.

the difference between the third and first quartiles

the student body of a large university consists of 61% female students. a random sample of 8 students is selected. what is the random variable in this experiment?

the number of female students out of 8

40% of all registered voters in the national election are female. a random sample of 5 voters is selected. what is the random variable in this experiment?

the number of female voters out of 5

two events are mutually exclusive if______.

they have no sample points in common

outlier

unusually small number value with a z-score -3 or +3 might be an outlier

the descriptive measure NOT measured in the same units as the original data is the_____________.

variance

percentile

(100-p), top 10% is 90th percentile

the correlation coefficient ranges from which 2 values?

-1 and +1

correlation coefficient

-1 is a strong negative relationship. +1 is a strong positive relationship. closer to 0, the weaker

Sandy's Pet Center grooms large and small dogs. it takes Sandy 20 minutes to groom a small dog and 70 minutes to groom a large dog. large dogs account for 40% of Sandy's business. Sandy has 5 appointments tomorrow. what is the probability that 4 appointments tomorrow are for large dogs?

.0768

if P(A|B)=.3 and P(B)=.8, then_____.

.24

Five Cs Bank issues credit cards to its customers. In the past 3.4% of the out-of-state nonfraudulent credit card transactions were made at gasoline stations and 9.2% of the out-of-state fraudulent credit card transactions were made at gasoline stations. Based on historical transactions 97.7% of out-of-state credit card transactions are legitimate while the rest of its out-of-state credit card transactions are fraudulent. An out-of-state credit card transaction took place at a gasoline station, what is the probability the transaction is fraudulent?

0.059886

a life insurance company has determined that each week an average of 9 claims are filed in its Denver branch. what is the probability that exactly 5 claims will be filed during the next week?

0.060727

if A and B are independent events with P(A)=0.301 and P(B)=0.253, then P(A ∩ B)=_________

0.07615 (multiply the two numbers)

The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3. Refer to exhibit 5-11. the probability there are 8 more occurrences in 10 minutes is_________.

0.0771

in a binomial experiment, the probability of success is 0.46. what is the probability of 7 successes in 20 trials?

0.11216

the student body of a large university consists of 61% female students. a random sample of 8 students is selected. what is the probability among the students in the sample at least 7 are female?

0.117224

What is P(YES warranty | PAID CASH)? Warranty purchase PAID CASH STORE CREDIT ACCT CREDIT CARD YES 2 12 53 NO 9 20 71

0.181818

a production process produces 5.9% defective parts. a sample of 21 parts from the production process is selected. what is the probability that the sample contains exactly 2 defective parts?

0.230211

Precision Manufacturing gets 41% of its valves from Hammond Inc. and the rest of its valves from SINGER. Historically 0.12% of the valves it gets from Hammond Inc. are defective and 0.03% of the valves it gets from SINGER are defective. A valve is found to be defective, what is the probability the valve came from SINGER?

0.26457

What is the probability that a customer is in the 18-30 age group? Product Preference age 18-30 age 31-45 age 46+ Strawberry 33 36 32 Blueberry 14 23 27

0.284848

what is the probability that a customer is in the 46+ age group?Product Preference age 18-30 age 31-45 age 46+ Strawberry 53 27 33 Blueberry 22 25 27

0.320856

Performance Boating gets 52% of its sparks plugs from Sparks Unlimited and the rest of its spark plugs from United Engines. In the past 5% of the spark plugs from Sparks Unlimited are defective and 11% of the spark plugs from United Engines are defective. A spark plug is defective, what is the probability it came from Sparks Unlimited?

0.32995

what is the probability that a customer is in tempe or prefers chocolate or both? Product Preference Flagstaff Tempe Tucson Vanilla 43 71 31 Chocolate 35 61 32

0.728938

three applications to a local university are checked to determine whether each applicant is male or female. the number of sample points in this experiment is _________.

8

20% of people at a company picnic got food poisoning. what percent of people at the picnic did NOT get food poisoning?

80%

excel's ___________ function can be used to compute the mean.

AVERAGE

events A and B are mutually exclusive. which of the following statements is also true?

P(A ∪ B) = P(A) + P(B)

interquartile range

Q3-Q1

a marketing manager instructs his team to make 80 telephone calls to attempt to sell an insurance policy. the random variable in this experiment is the number of sales made. this random variable is a ______________.

discrete random variable

when dealing with the number of occurrences of an even over a specified interval of time or space and when the occurrence or nonoccurrence in any interval is independent of the occurrence or nonoccurrence in any other interval, the appropriate probability distribution is a _______________.

poisson distribution

a numerical measure, such as a mean, computed from a population is known as__________.

population parameter

revised probabilities of events based on additional information are________.

posterior probabilites

standard deviation

square root of variance

what are quartiles used for?

summarizing the data and their distribution