UCF QMB 3200 FINAL EXAM
QUESTIONS & ANSWERS(RATED A+)
Doubling the size of the sample will - ANSWERreduce the standard error of the mean
The sample mean is the point estimator of - ANSWERU
A simple random sample of size n from an infinite population of size N is to be selected.
Each possible sample should have - ANSWERthe same probability of being selected
Which of the following statements regarding the sampling distribution of sample means
is incorrect? - ANSWERThe 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 - ANSWEReach 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
- ANSWERcentral limit theorem.
Cluster sampling is - ANSWERa probability sampling method.
The central limit theorem states that - ANSWERif 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 -
ANSWERsample statistic
The sampling distribution of is the - ANSWERprobability distribution of all possible
values of the sample proportion.
Which of the following is not a symbol for a parameter? - ANSWERS.
The sample statistic characteristic s is the point estimator of - ANSWERσ..
The distribution of values taken by a statistic in all possible samples of the same size
from the same population is called a - ANSWERsampling distribution.
Which of the following is a point estimator? - ANSWERS.
,As a rule of thumb, the sampling distribution of the sample proportion can be
approximated by a normal probability distribution when - ANSWERn(1 - p) ≥ 5 and np ≥
5.
A sample of 92 observations is taken from an infinite population. The sampling
distribution of is approximately - ANSWERnormal 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 -
ANSWERwhen 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 - ANSWERThe sample
Which of these best describes a sampling distribution of a statistic? - ANSWERIt 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 -
ANSWERsampling 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 - ANSWERfour 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 - ANSWERincreasing 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? - ANSWER0.50
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? - ANSWERA t
distribution should be used because σ is unknown.
The z value for a 99% confidence interval estimation is - ANSWER2.58
In an interval estimation for a proportion of a population, the critical value of z at 99%
confidence is - ANSWER2.576.
, In interval estimation, as the sample size becomes larger, the interval estimate -
ANSWERbecomes narrower.In general, higher confidence levels provide larger
confidence intervals.
One way to have high confidence and a small margin of error is to - ANSWERincrease
the sample size.
For a fixed sample size, n, in order to have a higher degree of confidence, the margin of
error and the width of the interval - ANSWERmust be larger.
The probability that the interval estimation procedure will generate an interval that does
not contain µ is known as the - ANSWERlevel of significance.
As the sample size increases, the margin of error - ANSWERdecreases.
When the level of confidence decreases, the margin of error - ANSWERbecomes
smaller.
An approximate value of a population parameter that provides limits and believed to
contain the value of the parameter is known as - ANSWERthe interval estimate.
To compute the necessary sample size for an interval estimate of a population mean, all
of the following procedures are recommended when σ is unknown except -
ANSWERusing σ = 1.
For the interval estimation of μ when σ is known and the sample is large, the proper
distribution to use is - ANSWERthe normal distribution.
What is the symbol for the sample mean? - ANSWERX bar
A student wants to determine if pennies are really fair, meaning equally likely to land
heads up or tails up. He flips a random sample of 50 pennies and finds that 28 of them
land heads up. What are the appropriate null and alternative hypotheses? -
ANSWERH0: p=.5, Ha:p not =.5.
For a lower tail test, the p-value is the probability of obtaining a value for the test
statistic - ANSWERat least as small as that provided by the sample.
The average hourly wage of computer programmers with 2 years of experience has
been $21.80. Because of high demand for computer programmers, it is believed there
has been a significant increase in the average wage of computer programmers. To test
whether there has been an increase, the correct hypotheses to be tested are -
ANSWERH0:u<21.80, Ha: u>21.80.
In hypothesis testing, the tentative assumption about the population parameter is called
- ANSWERthe null hypothesis.
QUESTIONS & ANSWERS(RATED A+)
Doubling the size of the sample will - ANSWERreduce the standard error of the mean
The sample mean is the point estimator of - ANSWERU
A simple random sample of size n from an infinite population of size N is to be selected.
Each possible sample should have - ANSWERthe same probability of being selected
Which of the following statements regarding the sampling distribution of sample means
is incorrect? - ANSWERThe 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 - ANSWEReach 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
- ANSWERcentral limit theorem.
Cluster sampling is - ANSWERa probability sampling method.
The central limit theorem states that - ANSWERif 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 -
ANSWERsample statistic
The sampling distribution of is the - ANSWERprobability distribution of all possible
values of the sample proportion.
Which of the following is not a symbol for a parameter? - ANSWERS.
The sample statistic characteristic s is the point estimator of - ANSWERσ..
The distribution of values taken by a statistic in all possible samples of the same size
from the same population is called a - ANSWERsampling distribution.
Which of the following is a point estimator? - ANSWERS.
,As a rule of thumb, the sampling distribution of the sample proportion can be
approximated by a normal probability distribution when - ANSWERn(1 - p) ≥ 5 and np ≥
5.
A sample of 92 observations is taken from an infinite population. The sampling
distribution of is approximately - ANSWERnormal 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 -
ANSWERwhen 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 - ANSWERThe sample
Which of these best describes a sampling distribution of a statistic? - ANSWERIt 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 -
ANSWERsampling 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 - ANSWERfour 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 - ANSWERincreasing 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? - ANSWER0.50
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? - ANSWERA t
distribution should be used because σ is unknown.
The z value for a 99% confidence interval estimation is - ANSWER2.58
In an interval estimation for a proportion of a population, the critical value of z at 99%
confidence is - ANSWER2.576.
, In interval estimation, as the sample size becomes larger, the interval estimate -
ANSWERbecomes narrower.In general, higher confidence levels provide larger
confidence intervals.
One way to have high confidence and a small margin of error is to - ANSWERincrease
the sample size.
For a fixed sample size, n, in order to have a higher degree of confidence, the margin of
error and the width of the interval - ANSWERmust be larger.
The probability that the interval estimation procedure will generate an interval that does
not contain µ is known as the - ANSWERlevel of significance.
As the sample size increases, the margin of error - ANSWERdecreases.
When the level of confidence decreases, the margin of error - ANSWERbecomes
smaller.
An approximate value of a population parameter that provides limits and believed to
contain the value of the parameter is known as - ANSWERthe interval estimate.
To compute the necessary sample size for an interval estimate of a population mean, all
of the following procedures are recommended when σ is unknown except -
ANSWERusing σ = 1.
For the interval estimation of μ when σ is known and the sample is large, the proper
distribution to use is - ANSWERthe normal distribution.
What is the symbol for the sample mean? - ANSWERX bar
A student wants to determine if pennies are really fair, meaning equally likely to land
heads up or tails up. He flips a random sample of 50 pennies and finds that 28 of them
land heads up. What are the appropriate null and alternative hypotheses? -
ANSWERH0: p=.5, Ha:p not =.5.
For a lower tail test, the p-value is the probability of obtaining a value for the test
statistic - ANSWERat least as small as that provided by the sample.
The average hourly wage of computer programmers with 2 years of experience has
been $21.80. Because of high demand for computer programmers, it is believed there
has been a significant increase in the average wage of computer programmers. To test
whether there has been an increase, the correct hypotheses to be tested are -
ANSWERH0:u<21.80, Ha: u>21.80.
In hypothesis testing, the tentative assumption about the population parameter is called
- ANSWERthe null hypothesis.
