Suppose that you believe that a cubic relationship exists between the independent
variable (of time) and the dependent variable Y . Which of the following would
represent a valid linear regression model?
A healthcare executive is using regression to predict total revenues. She has decided to
include both patient length of stay and insurance type in her model. Insurance type can
be grouped into three categories: Government-Funded, Private-Pay, and ‘Other’. Her
model is
Y = b .
Y = b0 + b1 X1 + b2 X2 + b3 X3 .
Y = b0 + b1 X1 + b2 X2 + b3 X3 + b4 X4 .
Y = b0 + b1 X1 .
Y = b0 + b1 X1 + b2 X2 .
Which distribution is helpful in testing hypotheses about variances?
exponential distribution
binomial distribution
Poisson distribution
normal distribution
F distribution
The number of cell phone minutes used by high school seniors follows a normal
distribution with a mean of 500 and a standard deviation of 50. What is the probability
that a student uses more than 350 minutes?
0.999
0.382
0.001
0.618
none of the above
Which of the following is not true about continuous random variables?
Some may be described by uniform distributions or exponential distributions.
The area under each of the curves represents probabilities.
The entire area under each of the curves equals one.
They have an infinite set of values.
They are useful for describing a discrete probability distribution.
In a distribution that is skewed to the right, what is the relationship of the mean,
median, and mode?
median>mean>mode
mode>median>mean
mode>mean>median
mean>median>mode
median<mode<mean
Suppose the number of babies born each hour at a hospital follows a Poisson
distribution with a mean of 4. Some people believe that the presence of a full moon
increases the number of births that take place. Suppose during the presence of a full
moon, the hospital experienced eight consecutive hours with more than five births each
hour. Based on this fact, comment on the belief that the full moon increases the number
of births.
The belief is not supported as the probability of observing this many births is 0.215.
The belief is supported as the probability of observing this many births would be
0.215.
The belief is not supported as the probability of observing this many births is
0.00000457.
The belief is supported as the probability of observing this many births would be
0.00000457.
none of the above
Suppose that the random variable x has an exponential distribution with θ = 10 .
Find the probability that P(X ≧10) .
.247596
.656986
.505698
.367879
.436598
Which expression represents the sum of the squares of the observations in a data set?
A confidence interval for ( μ1 − μ2 ) is (−5, 8) . Which of the following inferences is
correct?
no significant difference between means
μ1 < μ2
μ1 > μ2
μ1 ≠ μ2
none of the above
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