Data that provide labels or names for categories of like items are known as
qualitative data
quantitative data
label data
category data
A numerical measure of linear association between two variables is the
variance
covariance
standard deviation
coefficient of variation
If P(A) = 0.50 , P(B) = 0.60 , and P(A∩ B) = 0.30 ; then events A and B are
mutually exclusive events
not independent events
independent events
not enough information is given to answer this question
A probability distribution showing the probability of x successes in n trials, where
the probability of success does not change from trial to trial, is termed a
uniform probability distribution
binomial probability distribution
hypergeometric probability distribution
normal probability distribution
Which of the following is not a characteristic of the normal probability distribution?
symmetry
The total area under the curve is always equal to 1.
99.72% of the time the random variable assumes a value within plus or minus 1
standard deviation of its mean
The mean is equal to the median, which is also equal to the mode
The standard deviation of a point estimator is called the
standard deviation
standard error
point estimator
variance of estimation
A 95% confidence interval for a population mean is determined to be 100 to 120. If the
confidence coefficient is reduced to 0.90, the interval of μ
becomes narrower
becomes wider
does not change
becomes 0.1
If the level of significance of a hypothesis test is raised from .01 to .05, the probability
of a Type II error
will also increase from .01 to .05
will not change
will decrease
will increase
If two independent large samples are taken from two populations, the sampling
distribution of the difference between the two sample means
can be approximated by a Poisson distribution
will have a variance of one
can be approximated by a normal distribution
will have a mean of one
The mean square is the sum of squares divided by
the total number of observations
its corresponding degrees of freedom
its corresponding degrees of freedom minus one
None of these alternatives is correct
Two measures are given by X +Y and X −Y , respectively, where X is a Poisson
(0.5) random variable and Y is a uniform (0, 1) random variable. Suppose that X
and Y are independent.
(一) Compute E(X +Y) ; E(X −Y) . (10%)
(二) Compute Var(X −Y) . (5%)
Compute the moment generating function of a normal random variable X with
parameters μ and σ 2 . (10%)
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