YAI 19

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102) Employees of a local company are classified according to gender and job type. The following table summarizes the number of people in each job category.
Male (M) Female (F)
Job
Administrative (AD) 110 10
Salaried staff (SS) 30 50
Hourly staff (HS) 60 40
If an employee is selected at random, what is the probability that the employee is female given that the employee is a salaried staff member.
A) .1667
B) .50
C) .60
D) .625
E) .70

103) A __________ probability is the altered marginal probability of an event based on additional information.
A) posterior
B) joint
C) marginal
D) conditional
E) A and B

104) Mutually exclusive events are
A) events with identical probabilities
B) events that have no outcomes in common
C) events that have no effect on each other
D) all of the above

105) Bayesian analysis involves a(n) __________ probability.
A) a priori
B) posterior
C) joint
D) relative frequency

106) In a __________ distribution, for each of n trials, the event always has the same probability of occurring.
A) binomial
B) joint
C) frequency
D) standard

107) Experiments with repeated independent trials will be described by the binomial distribution if
A) each trial result influences the next
B) each trial has exactly 2 outcomes whose probabilities do not change
C) the trials are continuous
D) the time between trials is constant

108) In a binomial distribution, for each of n trials, the event
A) time between trials is constant
B) always has the same probability of occurring
C) result of the first trial influence the next trial
D) trials are continuous

109) A fair die is rolled nine times. What is the probability that an odd number (1,3 or 5) will occur less than 3 times?
A) .0899
B) .2544
C) .7456
D) .9101
E) .9916

110) A fair die is rolled 8 times. What is the probability that an even number (2,4, 6) will occur between 2 and 4 times?
A) .1640
B) .2188
C) .4922
D) .6016
E) .8204

111) A company markets educational software products, and is ready to place three new products on the market. Past experience has shown that for this particular software, the chance of “success” is 80%. Assume that the probability of success is independent for each product. What is the probability that exactly 1 of the 3 products is successful?
A) 0.80
B) 2.4
C) 0.032
D) 0.24
E) 0.096

112) __________ is a measure of the dispersion of random variable values about the expected value or mean.
A) Standard deviation
B) Sample mean
C) Population mean
D) Variance
E) A and D

113) An automotive center keeps tracks of customer complaints received each week. The probability distribution for complaints can be represented as a table or a graph, both shown below. The random variable xi represents the number of complaints, and p(xi) is the probability of receiving xi complaints.
xi 0 1 2 3 4 5 6
p(xi) 0.1 0.15 0.18 0.2 0.2 0.1 0.07
What is the average number of complaints received per week?
A) 2.12
B) 3.32
C) 4.12
D) 2.83
E) None of the above

114) The expected value of the standard normal distribution is equal to
A) 0
B) 1
C) 1.5
D) 2
E) 2.5

115) The area under the normal curve represents probability, and the total area under the curve sums to
A) 0
B) 0.5
C) 1
D) 2

116) The __________ and variance are derived from a subset of the population data and are used to make inferences about the population.
A) Population variance
B) Population standard deviation
C) population mean
D) sample mean
E) sample range

117) Under the normal curve, the area between z=1 and z =-2 includes approximately __________ of the values.
A) 99%
B) 98%
C) 95%
D) 85%
E) 82%

118) For the normal distribution, the mean plus and minus 1.96 standard deviations will include what percent of the observations?
A) 80%
B) 84%
C) 90%
D) 95%
E) 97%

119) A jar of jelly is normally distributed with a mean of 16 oz and a standard deviation of 0.02 oz. What is the probability that a jar of jelly contains less than 16 oz?
A) .1915
B) .3085
C) .5000
D) .7257
E) .8413

120) A jar of jelly is normally distributed with a mean of 16 oz and a standard deviation of 0.02 oz. What is the probability that a jar of jelly contains more than 16.03 oz?
A) .0668
B) .1587
C) .3413
D) .4332
E) .9332

121) Under the normal curve, the area between z=2 and z =-2 includes __________ of the values.
A) 98%
B) 96%
C) 95%
D) 93%
E) 90%

122) The metropolitan airport commission is considering the establishment of limitations on noise pollution around a local airport. At the present time, the noise level per jet takeoff in one neighborhood near the airport is approximately normally distributed with a mean of 100 decibels and a standard deviation of 3 decibels. What is the probability that a randomly selected jet will generate a noise level of more than 105 decibels?
A) 0.0228
B) 0.0475
C) 0.0485
D) 0.0500
E) None of the above

123) For some positive value of Z, the probability that a standard normal variable is between 0 and Z is 0.2910. The value of Z is:
A) 0.17
B) 0.81
C) 1.25
D) 1.65

124) For some value of Z, the probability that a standard normal variable is below Z is 0.3783. The value of Z is:
A) -0.81
B) -0.31
C) 0.82
D) 1.55

125) For some positive value of Z, the probability that a standard normal variable is between 0 and Z is 0.3554. The value of Z is:
A) 0.31
B) 0.36
C) 0.95
D) 1.06

126) If we know that the length of time it takes a college student to find a parking spot in the library parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of 1 minute, find the probability that a randomly selected college student will find a parking spot in the library parking lot in less than 3 minutes.
A) 0.3551
B) 0.3085
C) 0.2674
D) 0.1915

127) Assume that it takes a college student an average of 5 minutes to find a parking spot in the main parking lot. Assume also that this time is normally distributed with a standard deviation of 2 minutes. Find the probability that a randomly selected college student will take between 2 and 6 minutes to find a parking spot in the main parking lot.
A) 0.1950
B) 0.4772
C) 0.4332
D) 0.6247

128) Assume that it takes a college student an average of 5 minutes to find a parking spot in the main parking lot. Assume also that this time is normally distributed with a standard deviation of 2 minutes. What time is exceeded by approximately 75% of the college students when trying to find a parking spot in the main parking lot?
A) 3.5 minutes
B) 5.75 minutes
C) 6.36 minutes
D) 9.2 minutes

129) The owner of a seafood market determined that the average weight for a crab is 1.6 pounds with a standard deviation of 0.4 pound. What weight is exceeded by 2% of all of the crabs? (Assume the weights are normally distributed.)
A) 0.78 pounds
B) 1.82 pounds
C) 2.42 pounds
D) 4.36 pounds

130) A professor would like to assign grades such that 5% of students receive As. If the exam average is 62 with a standard deviation of 13, what grade should be the cutoff for an A? (Round your answer.)
A) 80
B) 83
C) 90
D) 93

131) A professor would like to assign grades such that 7% of students receive Fs. If the exam average is 62 with a standard deviation of 13, what grade should be the cutoff for an F? (Round your answer.)
A) 43
B) 49
C) 50
D) 55