A small computing center has found that the number of jobs submitted per day to its computers
has a distribution that is approximately mound-shaped and symmetric, with a mean of 85 jobs
and a standard deviation of 5.
Where do we expect approximately 95 of the distribution to
fall?
A) between 70 and 100 jobs per day B) between 80 and 90 jobs per day
C) between 75 and 95 jobs per day D) between 95 and 100 jobs per day
Q. 2A sociologist recently conducted a survey of citizens over 60 years of age who have net worths
too high to qualify for Medicaid but have no private health insurance.
The ages of the 25
uninsured senior citizens were as follows:
68 73 66 76 86 74 61 89 65 90 69 92 76
62 81 63 68 81 70 73 60 87 75 64 82
Suppose the mean and standard deviation are 74.04 and 9.75, respectively. If we assume that the
distribution of ages is mound-shaped and symmetric, what percentage of the respondents will
be between 64.29 and 93.54 years old?
A) approximately 81.5 B) approximately 95
C) approximately 68 D) approximately 84
Q. 3Suppose the probability of an athlete taking a certain illegal steroid is 10. A test has been
developed to detect this type of steroid and will yield either a positive or negative result.
Given
that the athlete has taken this steroid, the probability of a positive test result is 0.995. Given that
the athlete has not taken this steroid, the probability of a negative test result is 0.992. Given that
a positive test result has been observed for an athlete, what is the probability that they have
taken this steroid?
A) 0.9552 B) 0.9325 C) 0.9928 D) 0.0995
Q. 4The mean x of a data set is 18, and the sample standard deviation s is 2. Explain what
the interval (12, 24 ) represents.
What will be an ideal response?
Q. 5Suppose that B1 and B2 are mutually exclusive and complementary events, such that P(B1 ) = .6
and P(B2 ) = .4. Consider another event A such that P(A B1 ) =.2 and P(A B2 ) = .5. Find P(B1
A).
A) .375 B) .800 C) .625 D) .240
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