The Central Limit Theorem permits us to draw conclusions about a population based on
a sample alone, without having any knowledge about the distribution of that population.
And this works no matter what the sample size is.
If there are two unbiased estimators of a parameter, the one whose variance is smaller is
said to be relatively efficient.
The F -test of the randomized block design of the analysis of variance has the same
requirements as the independent samples design; that is, the random variable must be
normally distributed and the population variances must be equal.
If the coefficient of correlation r = 0 , there can be no linear relationship between the
dependent variable y and the independent variable x .
Twenty-five percent of a sample of 200 professional tennis players indicated that their
parents did not play tennis. Based on this sample, we estimate that approximately 25%
of the parents of all professional tennis players did not play tennis, plus or minus 5%.
This is an example of using inferential statistics.
Most statistical software print a second R2 statistic, called the coefficient of
determination adjusted for degrees of freedom, which has been adjusted to take into
account the sample size and the number of independent variables.
A self-selected sample is the group of individuals who were randomly selected to be in
the sample, then agreed to participate in the study.
A data sample has a mean of 107, a median of 122, and a mode of 134. The distribution
of the data is positively skewed.
In a criminal trial, a Type II error is made when an innocent person is acquitted.
When constructing confidence interval estimate of μ , doubling the sample size n
decreases the width of the interval by half.
A researcher conducts a study where she divides subjects into two groups, gives each
group a certain treatment, and records their responses. What type of data collection is
being used here?
An experiment;
Direct observation;
A survey;
A census.
For a sample size of 1, the sampling distribution of the mean is normally distributed:
Regardless of the shape of the population;
Only if the population values are larger than 30;
Only if the population is normally distributed;
None of these choices.
Suppose the value of your chi-squared test statistic in a goodness-of-fit test is equal to
0. What do you conclude?
Reject H0 . Conclude that the least one proportion is not equal to its specified
value;
Fail to reject H0 . Not enough evidence to say the proportions are different from
what is listed in H0 ;
Not enough information; need the degrees of freedom for the test;
None of these choices.
After constructing a confidence interval estimate for a population mean, you believe
that the interval is useless because it is too wide. In order to correct this problem, you
need to:
Increase the population standard deviation;
Increase the sample size;
Increase the level of confidence;
Increase the sample mean.
Which of these measures of central location is not sensitive to extreme values?
The mean;
The median;
The mode;
The standard deviation.
Which of the following conclusions is not an appropriate conclusion from a hypothesis
test?
Reject H0 . Sufficient evidence to support H1 ;
Fail to reject H0 . Insufficient evidence to support H1 ;
Accept H0 . Sufficient evidence to support H0 ;
All of these choices are true.
Which of the following is an example of a nonsampling error?
Some incorrect responses are recorded.
Responses are not obtained from all members of the sample.
Some members of the target population cannot possibly be selected for the sample.
All of these choices are true.
Which of the following statement about multiple comparison methods is false?
They are to be use once the F -test in ANOVA has been rejected.
They are used to determine which particular population means differ.
There are many different multiple comparison methods but all yield the same
conclusions.
All of these choices are true.
As a general rule, the normal distribution is used to approximate the sampling distribution
of the sample proportion only if:
The sample size n is greater than 30.
The population proportion p is close to 0.50.
The underlying population is normal.
np and n(1− p) are both greater than or equal to 5.
In a two-factor ANOVA, there are levels for factor A , 5 levels for factor B , and 3
observations for each combination of factor A and factor B levels. The number of
treatments in this experiment equals:
60
25
20
16
Is a standard deviation of 10 a large number indicating great variability, or is it small
number indicating little variability? To answer this question correctly, one should look
carefully at the value of the:
Mean;
Standard deviation;
Coefficient of variation;
Mean dividing by the standard deviation.
In a multiple regression model, the probability distribution of the error variable ε is
assumed to be:
Normal;
Non-normal;
Positively skewed;
Negatively skewed.
Which of the following will never be a required condition of a nonparametric test?
Data are ordinal;
Data are interval;
The samples are drawn from normally distributed populations;
The populations being compared are identical in spread and shape.
An unbiased estimator of a population parameter is defined as:
An estimator whose expected value is equal to the parameter;
An estimator whose variance is equal to one;
An estimator whose expected value is equal to zero;
An estimator whose variance goes to zero as the sample size goes to infinity.
It is desired to estimate the average total compensation of CEOs in the service industry.
Data were randomly collected from 18 CEOs and 95% confidence interval was
calculated to be ($2,190,000, $4,720,000). Based on the interval above, do you believe
the actual average total compensation of CEOs in the service industry could be
$3,000,000?
Yes, and I am sure of that;
Yes, and I am 95% confident of that;
No, and I am sure of that;
No, and I am 95% confident of that.
At North Kaohsiung College, administrators want to determine the average commuting
distance for their students who commute to school. They randomly select 200 students
who commute and ask them the distance of their commute to campus. From this group a
mean of 17.5 km is computed. (8%)
(一) Describe/find the parameter.
(二) Describe/find the statistic.
(三) Describe the population.
(四) Describe the sample.
What is meant by nonresponse error? What the impacts will nonresponse error have on
research results? (8%)
A survey of a magazine’s subscribers indicates that 50% own a house, 80% own a car,
and 90% of the homeowners also own a car. What proportion of subscribers: (6%)
(一) Own both a car and a house?
(二) Own a car or a house, or both?
(三) Own neither a car nor a house?
What is multicollinearity? What the impacts will multicollinearity have on multiple
regression models? How do you go about checking for multicollinearity? (8%)
Before leaving a particular restaurant, customers are asked to respond to the questions
listed below. For each question, determine whether the possible responses are interval,
nominal, or ordinal. (5%)
(一) What is the approximate distance (in miles) between this restaurant and your
residence?
(二) Have you ever eaten at this restaurant before?
(三) On how many occasions have you eaten at the restaurant before?
(四) Which of the following attributes of this restaurant do you find most attractive:
service, prices, quality of the food, or the menu?
(五) What is your overall rating of the restaurant: excellent, good, fair, or poor?
Discuss on advantage and one disadvantage of a self-administered survey as a method
of data collection. (5%)
Researchers claim that 60 tissues is the average number of tissues a person uses during
the course of a cold. The company who makes CleanTis brand tissues thinks that fewer
of their tissues are needed. What are their null and alternative hypotheses? (4%)
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