An estimator is said to be consistent if:
it is an unbiased estimator
the variance of the estimator is close to one
the expected value of the estimator is known and positive
it is an unbiased estimator and the difference between the estimator
and the population parameter grows smaller as the sample size grows
larger
None of the above
Which of the following statements is NOT correct?
The sample mean is an unbiased estimator of the population mean
The sample proportion is an unbiased estimator of the population
proportion
The sample standard deviation is an unbiased estimator of the
population standard deviation
The difference between two sample means is an unbiased estimator of
the difference between two population means
None of the above
The sample size needed to estimate a population mean within 2 units with
a 95% confidence when the population standard deviation equals 8 is?
62
72
82
92
None of the above
The power of a test is denoted by: (for θ ∈H1 )
β
1 - β
α
1 - α
χ 2
A robust estimator is one that:
is unbiased and symmetrical about zero
is consistent and is also mound-shaped
is efficient and less spread out
is not sensitive to moderate departure from the assumption of normality
in the population
None of the above
A sample of size 125 selected from one population has 55 successes, and a
sample of size 140 selected from a second population has 70 successes. The
test statistic for testing the equality of the population proportions equal to:
−0.060
0.940
−0.977
−0.472
None of the above
To determine whether a single coin is fair, the coin was tossed 100 times,
and head was observed 60 times. The value of the test statistic is
2
6
20
60
None of the above
In the two-way ANOVA where a is the number of factor A levels, b is
the number of factor B levels, and r in the number of replicates, the
number of degrees of freedom for interaction is:
ab − r
abr −1
(a −1)(b −1)(r −1)
ab(r −1)
None of the above
A nonparametric method to compare two populations, when the samples
are matched pairs and the data are ordinal, is the:
Sign test
Run test
Wilcoxon rank sum test
Mann-Whitney U test
None of the above
Which of the following is not an advantage of multiple regression as
compared with analysis of variance?
Multiple regression can be used to estimate the relationship between
the dependent variable and independent variables
Multiple regression handles problems with more than two independent
variables easier than analysis of variance
Multiple regression handles qualitative variables better than analysis of
variance
All of the above are advantages of multiple regression as compared with
analysis of variance
None of the above
Effect of x1 on y remains the same no matter what the value of x2
Effect of x1 on y remains the same no matter what the value of x1
Only difference in the four equations produced is the coefficient of x2
Not enough information is given to answer this question
None of the above
Suppose that we want to model the randomized block design of the
analysis of variance with, say, three treatments and four blocks. How
many indicator variable should we create?
7 indicator variables
5 indicator variables
6 indicator variables
4 indicator variables
Nona of the above
If X and Y are random variables with V(X) = 7.5 , V(Y ) = 6 and
COV(X,Y ) = 4 , then what is the value of V(2X + 3Y ) ?
133
37
88
132
None of the above
Which of the following models might be appropriate to describe a new
product that has experienced a rapid early growth rate followed by the
inevitable leveling off?
Autoregressive model
Linear model for long-term trend
Quadratic model for long-term trend
Lognormal model for long-term trend
None of the above
An investment firm has classified its clients according to their gender and
the composition of their investment portfolio (primarily bonds, primarily
stocks, or a balanced mix of bonds and stocks). The proportions of clients
falling into the various categories are shown in the following table. Please
find the probability that the employee selected is male, given that the
employee has an unbalanced portfolio.
0.633
0.625
0.3968
0.375
None of the above
(1) What is the within groups degrees of freedom?
(2) What is the total number of degrees of freedom?
(3) What is the between group means square?
(4) What is the null hypothesis?
(5) At a significance level of 1%, What is the proper conclusion?
(1) What is the coefficient of determination? Explain what this statistic
tells you about the model.
(2) Do these results allow us to conclude at the 5% significance level that
the model is useful in predicting the team’s winning percentage?
10
(3) Test to determine at the 10% significance level if the linear term and
the x2 term should be retained.
(4) Based on the result of (2) and (3), please predict the value of winning
team’s percentage with 12 years of professional experience.
可觀看題目詳解,並提供模擬測驗!(免費會員無法觀看研究所試題解答)