The covariance of two variables X and Y:
must be between –1 and +1
must be positive
can be positive or negative
must be less than –1
Whenever p = 0.1 and n is small, the binomial distribution will be:
systematic
right-skewed
left-skewed
None of the above
Let X be a Poisson random variable with μ = 2 . P(X > 0) =
0.665
0.765
0.865
0.965
Patients arriving at an outpatient clinic follow an exponential distribution
at a rate 1 patient per hour. What is the probability that a randomly
chosen arrival is to be in more than 1 hour?
0.685
0.500
0.368
0.133
If two random samples if size 30 and 36 are selected independently from
two population with means of 78 and 85, and standard deviations of 12 and
15, respectively, then the standard error of the difference between the two
sample means is:
0.904
3.324
3.391
The sample size needed to estimate a population mean to within 50 units
was found to be 97. If the population standard deviation was 250, then the
confidence level used was
99%
95%
90%
80%
If a test of hypothesis has a Type I error probability of .05, this means that
if the null hypothesis is true, we don’t reject it 5% of the time
if the null hypothesis is true, we reject it 5% of the time
if the null hypothesis is false, we don’t reject it 5% of the time
if the null hypothesis is false, we reject it 5% of the time
The power of a test is measured by its capability of
rejecting a null hypothesis that is true
not rejecting a null hypothesis that is true
rejecting a null hypothesis that is false
not rejecting a null hypothesis that is false
The statistic (n −1)s2 σ2 is chi-squared distributed with n −1 degrees of
freedom only if:
the population is normally distributed with variance equal to σ 2
the population is normally distributed with variance equal to s2
the sample has a student t distribution with degrees of freedom equal to
n −1
all of the above statements are correct
After calculating the sample size needed to estimate a population
proportion to within 0.04, your statistics professor told you that the
maximum allowable error must be reduced to just .01. If the original
calculation led to a sample size of 800, the sample size will now have to be:
1600
3200
12,800
6400
If we are testing for the difference between the means of two independent
populations with equal variances, samples of n1 = 15 and n2 = 15 are
taken, then the number of degrees of freedom is equal to:
29
28
14
13
Which of the following statements is correct regarding the percentile points
of the F-distribution?
F0.05,10, 20 = 1/ F0.95,10, 20
F0.05,10, 20 = 1/ F0.05,10, 20
F0.95,10, 20 = 1/ F0.95,10, 20
F0.95,10, 20 = 1/ F0.05,10, 20
A sample of size 100 selected from one population has 60 successes, and a
sample of size 150 selected from a second population has 95 successes. The
test statistic for testing the equality of the population proportion is around:
–0.53
0.73
–0.42
0.27
The process of using sample statistics to draw conclusions about true
population parameters is called
inferential statistics
the scientific method
sample method
descriptive statistics
The classification of student class designation (freshman, sophomore,
junior, senior) is an example of
a categorical random variable
a discrete random variable
a continuous random variable
a parameter
In order to draw a scatter diagram, we need interval data for
one variable
two variables
three variables
four variables
Which of the following is a correct statement?
The central location of highly skewed data may be more appropriately
measured by the median.
The shape of the distribution can help us determine the approximate
center of the distribution.
The shape of the distribution can help us determine whether the
observations are close to one another, or they are widely spread.
All of the above.
A marketing research firm, in conducting a comparative taste test,
provided four types of wine to a sample of households randomly selected
within the state. Which method of data collection is involved when people
are asked to compare the types of wines?
Published sources
Experimentation
Surveying
Direct observation
A posterior probability value is a prior probability value that has been
modified on the basis of new information
multiplied by a conditional probability value
divided by a conditional probability value
added to a conditional probability value
A function or rule that assigns a numerical value to each simple event of
an experiment is called:
a sample space
a probability tree
a probability distribution
a random variable
ASUS’s product manager in notebook is testing notebook users’ attitudes
on two TV commercials (endorsed either by 張忠謀 or by 林志玲) with two
levels of involvement (i.e., high vs. low involvement). 100 notebook users
are randomly assigned to one of four treatments, such that there are 25
observations in each treatment. An ANOVA analysis is conducted, and she
notices that audience’s attitude can be significantly influenced by the
interaction of endorser and involvement. If the interaction effect, (αβ )11 , of
TV commercial endorsed by 張忠謀 in high involvement is 2, then what
would be the interaction effect, (αβ )22 , of TV commercial endorsed by 林志
玲 in low involvement?
need more details to answer
0
2
-2
By following the above question, if the marketing manager also notices
that the main effect for endorser is not significant in ANOVA outcome,
then the expectation of mean squares for endorser would be?
smaller than the expectation of mean squares for interaction (MSAB)
smaller than the expectation of MSE
larger than the expectation of mean squares for involvement
larger than the expectation of the difference between MSAB and MSE
Which of the following statements is CORRECT?
In a one-way ANOVA, if the null hypothesis is rejected, then treatment
means are different from each other.
In a two-way ANOVA, total sum of squares is equal to the summation of
treatment sum of squares (including factor 1 sum of squares, factor 2
sum of squares, and interaction sum of squares) and error sum of
squares
ANOVA is one of linear statistical models: therefore, linear relationship
between dependent and independent variables can be examined by
ANOVA
D)In a two-way ANOVA with two levels for each factor and n observations
in each treatment, if (αβ )11 is greater than the square root of MSE,
then F* test statistics for interaction can only be greater than n
Sony’s manager in 3C SBU would like to compare customer satisfactions
on PS3 game console and Bravia LCD TV. 7-point Kikert scale is applied in
the measurement of customer satisfaction. For PS3 game console, the
sample mean for customer satisfaction is 5.8, and the standard deviation
for PS3 customers is 3.2. As for Bravia LCD TV, the sample mean for
customer satisfaction is 6.1, and the standard deviation for Bravia
customers is 1.6. Which of the following statements is CORRECT?
Since the mean difference is much smaller than both standard
deviations, the one-way ANOVA outcome is not supposed to reject the
null hypothesis
More information, such as degree of freedom, SSE and SSTR, is
required to determine whether or not the null hypothesis in the one-way
ANOVA is supposed to be rejected
The expectation of treatment mean square can be smaller than the
expectation of error mean square, especially when mean difference is
close to 0
One-way ANOVA is not supposed to be applied
Steve loves to study Insects. According to his study in his whole life (more
than 20 years), the concludes that whenever there is one spider observed in
his basement, the stock price of company A on that particular day would be
$11; whenever two spiders observed, stock price would be $12, and so on.
Steve’s observation can be exactly formulated as (stock price of company A)
= 10 + (number of spiders observed in the basement). No exception has
been identified. Which of the following is NOT correct?
Stock price of company A and number of spiders observed in the
basement are positively correlated
Since the two variables are positively correlated, Steve can apply
regression analysis, and the regression coefficient, β1 would also be positive
The correlation coefficient between stock price of company A and
number of spiders observed in the basement can not be made even
larger and larger
It is likely that in the next morning when Steve wins lottery, the
relationship between stock price of company A and number of spiders
observed in the basement may not follow the above formula
Its inclusion will introduce autocorrelation.
Its inclusion will introduce collinearity.
Its inclusion will inflate the standard errors of the estimated
coefficients.
Both (B) and (C)
What is the correct interpretation for the estimated coefficient for ADVT?
$1 increase in per person advertising expenditure by the manufacturer
will result in an estimated average increase of $2.35 on personal
consumption holding other variables constant.
A 100% increase in per person advertising expenditure by the
manufacturer will result in an estimated average increase of $2.35 on
personal consumption holding other variables constant.
A 100% increase in per person advertising expenditure by the
manufacturer will result in an estimated average increase of 2.35% on
personal consumption holding other variables constant.
A 1% increase in per person advertising expenditure by the
manufacturer will result in an estimated average increase of 2.35% on
personal consumption holding other variables constant.
In a goodness-of-fit test, suppose that a sample showed that the observed
frequency and expected frequency were equal for each cell i. Then, the null
hypothesis is
rejected at α = 0.05 but is not rejected at a = 0.025
not rejected at any α level
not rejected at α = 0.05 but is rejected at α = 0.025
rejected at any level α
Which of the following is CORRECT?
When using the χ 2 tests for independence, one should be aware that
expected frequencies that are too small will lead to too big a type I
error.
Chi-square test of independence requires that the number of expected
frequency in each cell to be at least 5.
When the parametric assumption on the distribution is met, a
nonparametric test is usually more powerful than a parametric test.
The squared difference between the observed and theoretical
frequencies should be large if there is no significant difference between
the proportions.
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