UCF QMB 3200 FINAL EXAM
QUESTIONS AND ANSWERS
Doubling the size of the sample will - Correct Answers -reduce the standard error of the
mean
The sample mean is the point estimator of - Correct Answers -U
A simple random sample of size n from an infinite population of size N is to be selected.
Each possible sample should have - Correct Answers -the same probability of being
selected
Which of the following statements regarding the sampling distribution of sample means
is incorrect? - Correct Answers -The standard deviation of the sampling distribution is
the standard deviation of the population.
A simple random sample of size n from an infinite population is a sample selected such
that - Correct Answers -each element is selected independently and is selected from the
same population
The fact that the sampling distribution of sample means can be approximated by a
normal probability distribution whenever the sample size becomes large is based on the
- Correct Answers -central limit theorem.
Cluster sampling is - Correct Answers -a probability sampling method.
The central limit theorem states that - Correct Answers -if the sample size n is large,
then the sampling distribution of the sample mean can be approximated by a normal
distribution.
The value of the _____ is used to estimate the value of the population parameter -
Correct Answers -sample statistic
The sampling distribution of is the - Correct Answers -probability distribution of all
possible values of the sample proportion.
Which of the following is not a symbol for a parameter? - Correct Answers -S.
The sample statistic characteristic s is the point estimator of - Correct Answers -σ..
,The distribution of values taken by a statistic in all possible samples of the same size
from the same population is called a - Correct Answers -sampling distribution.
Which of the following is a point estimator? - Correct Answers -S.
As a rule of thumb, the sampling distribution of the sample proportion can be
approximated by a normal probability distribution when - Correct Answers -n(1 - p) ≥ 5
and np ≥ 5.
A sample of 92 observations is taken from an infinite population. The sampling
distribution of is approximately - Correct Answers -normal because of the central limit
theorem.
The central limit theorem is important in Statistics because it enables reasonably
accurate probabilities to be determined for events involving the sample average -
Correct Answers -when the sample size is large regardless of the distribution of the
variable.
The distribution of values taken by a statistic in all possible samples of the same size
from the same population is the sampling distribution of - Correct Answers -The sample
Which of these best describes a sampling distribution of a statistic? - Correct Answers -
It is the distribution of all of the statistics calculated from all possible samples of the
same sample size.
The probability distribution of all possible values of the sample proportion is the -
Correct Answers -sampling distribution of p.
For a fixed confidence level and population standard deviation, if we would like to cut
our margin of error in half, we should take a sample size that is - Correct Answers -four
times as large as the original sample size.
We can reduce the margin of error in an interval estimate of p by doing any of the
following except - Correct Answers -increasing the planning value p* to .5.
When computing the sample size needed to estimate a proportion within a given margin
of error for a specific confidence level, what planning value of p should be used when
no estimate of p is available? - Correct Answers -0.50
A statistics teacher started class one day by drawing the names of 10 students out of a
hat and asked them to do as many pushups as they could. The 10 randomly selected
students averaged 15 pushups per person with a standard deviation of 9 pushups.
Suppose the distribution of the population of number of pushups that can be done is
approximately normal. Which of the following statements is true? - Correct Answers -A t
distribution should be used because σ is unknown.
, The z value for a 99% confidence interval estimation is - Correct Answers -2.58
In an interval estimation for a proportion of a population, the critical value of z at 99%
confidence is - Correct Answers -2.576.
In interval estimation, as the sample size becomes larger, the interval estimate - Correct
Answers -becomes narrower.In general, higher confidence levels provide larger
confidence intervals.
One way to have high confidence and a small margin of error is to - Correct Answers -
increase the sample size.
From a population that is normally distributed, a sample of 30 elements is selected and
the standard deviation of the sample is computed. For the interval estimation of μ, the
proper distribution to use is the - Correct Answers -t distribution with 29 degrees of
freedom.
As the number of degrees of freedom for a t distribution increases, the difference
between the t distribution and the standard normal distribution - Correct Answers -
becomes smaller.
The value added and subtracted from a point estimate in order to develop an interval
estimate of the population parameter is known as the - Correct Answers -margin of
error.
What is the symbol for the population mean? If the population follows a normal
distribution, the confidence interval is _____ and can be used for any sample size. If the
population does not follow a normal distribution, the confidence interval will be _____.
Which of the following choices correctly complete this statement? - Correct Answers -
exact; approximate.
The t value for a 99% confidence interval estimation based upon a sample of size 10 is -
Correct Answers -3.250.
To compute the necessary sample size for an interval estimate of a population
proportion, all of the following procedures are recommended when p is unknown except
- Correct Answers -using .95 as an estimate.
Using an α = .04, a confidence interval for a population proportion is determined to be
.65 to .75. If the level of significance is decreased, the interval for the population
proportion - Correct Answers -becomes wider.
For a fixed confidence level and population standard deviation, if we would like to cut
our margin of error to 1/3 of the original size, we should take a sample size that is -
Correct Answers -nine times as large as the original sample size.
QUESTIONS AND ANSWERS
Doubling the size of the sample will - Correct Answers -reduce the standard error of the
mean
The sample mean is the point estimator of - Correct Answers -U
A simple random sample of size n from an infinite population of size N is to be selected.
Each possible sample should have - Correct Answers -the same probability of being
selected
Which of the following statements regarding the sampling distribution of sample means
is incorrect? - Correct Answers -The standard deviation of the sampling distribution is
the standard deviation of the population.
A simple random sample of size n from an infinite population is a sample selected such
that - Correct Answers -each element is selected independently and is selected from the
same population
The fact that the sampling distribution of sample means can be approximated by a
normal probability distribution whenever the sample size becomes large is based on the
- Correct Answers -central limit theorem.
Cluster sampling is - Correct Answers -a probability sampling method.
The central limit theorem states that - Correct Answers -if the sample size n is large,
then the sampling distribution of the sample mean can be approximated by a normal
distribution.
The value of the _____ is used to estimate the value of the population parameter -
Correct Answers -sample statistic
The sampling distribution of is the - Correct Answers -probability distribution of all
possible values of the sample proportion.
Which of the following is not a symbol for a parameter? - Correct Answers -S.
The sample statistic characteristic s is the point estimator of - Correct Answers -σ..
,The distribution of values taken by a statistic in all possible samples of the same size
from the same population is called a - Correct Answers -sampling distribution.
Which of the following is a point estimator? - Correct Answers -S.
As a rule of thumb, the sampling distribution of the sample proportion can be
approximated by a normal probability distribution when - Correct Answers -n(1 - p) ≥ 5
and np ≥ 5.
A sample of 92 observations is taken from an infinite population. The sampling
distribution of is approximately - Correct Answers -normal because of the central limit
theorem.
The central limit theorem is important in Statistics because it enables reasonably
accurate probabilities to be determined for events involving the sample average -
Correct Answers -when the sample size is large regardless of the distribution of the
variable.
The distribution of values taken by a statistic in all possible samples of the same size
from the same population is the sampling distribution of - Correct Answers -The sample
Which of these best describes a sampling distribution of a statistic? - Correct Answers -
It is the distribution of all of the statistics calculated from all possible samples of the
same sample size.
The probability distribution of all possible values of the sample proportion is the -
Correct Answers -sampling distribution of p.
For a fixed confidence level and population standard deviation, if we would like to cut
our margin of error in half, we should take a sample size that is - Correct Answers -four
times as large as the original sample size.
We can reduce the margin of error in an interval estimate of p by doing any of the
following except - Correct Answers -increasing the planning value p* to .5.
When computing the sample size needed to estimate a proportion within a given margin
of error for a specific confidence level, what planning value of p should be used when
no estimate of p is available? - Correct Answers -0.50
A statistics teacher started class one day by drawing the names of 10 students out of a
hat and asked them to do as many pushups as they could. The 10 randomly selected
students averaged 15 pushups per person with a standard deviation of 9 pushups.
Suppose the distribution of the population of number of pushups that can be done is
approximately normal. Which of the following statements is true? - Correct Answers -A t
distribution should be used because σ is unknown.
, The z value for a 99% confidence interval estimation is - Correct Answers -2.58
In an interval estimation for a proportion of a population, the critical value of z at 99%
confidence is - Correct Answers -2.576.
In interval estimation, as the sample size becomes larger, the interval estimate - Correct
Answers -becomes narrower.In general, higher confidence levels provide larger
confidence intervals.
One way to have high confidence and a small margin of error is to - Correct Answers -
increase the sample size.
From a population that is normally distributed, a sample of 30 elements is selected and
the standard deviation of the sample is computed. For the interval estimation of μ, the
proper distribution to use is the - Correct Answers -t distribution with 29 degrees of
freedom.
As the number of degrees of freedom for a t distribution increases, the difference
between the t distribution and the standard normal distribution - Correct Answers -
becomes smaller.
The value added and subtracted from a point estimate in order to develop an interval
estimate of the population parameter is known as the - Correct Answers -margin of
error.
What is the symbol for the population mean? If the population follows a normal
distribution, the confidence interval is _____ and can be used for any sample size. If the
population does not follow a normal distribution, the confidence interval will be _____.
Which of the following choices correctly complete this statement? - Correct Answers -
exact; approximate.
The t value for a 99% confidence interval estimation based upon a sample of size 10 is -
Correct Answers -3.250.
To compute the necessary sample size for an interval estimate of a population
proportion, all of the following procedures are recommended when p is unknown except
- Correct Answers -using .95 as an estimate.
Using an α = .04, a confidence interval for a population proportion is determined to be
.65 to .75. If the level of significance is decreased, the interval for the population
proportion - Correct Answers -becomes wider.
For a fixed confidence level and population standard deviation, if we would like to cut
our margin of error to 1/3 of the original size, we should take a sample size that is -
Correct Answers -nine times as large as the original sample size.
