Exam 3
A Type I error is committed when
a true null hypothesis is rejected
As the degrees of freedom increase, the t distribution approaches the
Normal distribution
Read the t statistic from the table of t distributions and circle the correct answer. A one-tailed test (lower tail), a sample size of 10 at a .10 level of significance; t =
-1.383
Read the z statistic from the normal distribution table and circle the correct answer. A one-tailed test (lower tail) at a .063 level of significance; z =
-1.53
The sample size that guarantees all estimates of proportions will meet the margin of error requirements is computed using a planning value of p equal to
0.50
If an interval estimate is said to be constructed at the 90% confidence level, the confidence coefficient would be
0.9
If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient is
0.95
Read the t statistic from the table of t distributions and circle the correct answer. A two-tailed test, a sample of 20 at a .20 level of significance; t =
1.328
Read the t statistic from the table of t distributions and circle the correct answer. A one-tailed test (upper tail), a sample size of 18 at a .05 level of significance t =
1.740
It is known that the variance of a population equals 1,936. A random sample of 121 has been taken from the population. There is a .95 probability that the sample mean will provide a margin of error of
1.96 (44/sqrt(121) = 7.84
The z value for a 97.8% confidence interval estimation is
2.29
The use of the normal probability distribution as an approximation of the sampling distribution of p-bar is based on the condition that both np and n(1 - p) equal or exceed
5
A 95% confidence interval for a population mean is determined to be 100 to 120. If the confidence coefficient is reduced to 0.90, the interval for m
Becomes narrower
Using an a = 0.04, a confidence interval for a population proportion is determined to be 0.65 to 0.75. If the level of significance is decreased, the interval for the population proportion
Becomes wider
The probability that the interval estimation procedure will generate an interval that does not contain the actual value of the population parameter being estimated is the
Confidence coefficient
The ability of an interval estimate to contain the value of the population parameter is described by the
Confidence level
The confidence associated with an interval estimate is called the
Confidence level
As the sample size increases, the margin of error
Decreases
The t distribution is a family of similar probability distributions, with each individual distribution depending on a parameter known as the
Degrees of freedom
A random sample of 25 employees of a local company has been measured. A 95% confidence interval estimate for the mean systolic blood pressure for all company employees is 123 to 139. Which of the following statements is valid?
If the sampling procedure were repeated many times, 95% of the resulting confidence intervals would contain the population mean systolic blood pressure.
The test statistic F is the ratio
MSTR/MSE
When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as
Matched samples
A newspaper wants to estimate the proportion of Americans who will vote for Candidate A. A random sample of 1000 voters is taken. Of the 1000 respondents, 526 say that they will vote for Candidate A. Which Excel function would be used to construct a confidence interval estimate?
NORM.S.INV
A meteorologist stated that the average temperature during July in Chattanooga was 80 degrees. A sample of 32 Julys was taken. The correct set of hypotheses is
None of the other answers are correct.
The degrees of freedom associated with a t distribution are a function of the
Sample size
A two-tailed test is performed at a 5% level of significance. The p-value is determined to be 0.09. The null hypothesis
Should not be rejected because 0.09 > 0.05
For the interval estimation of m when s is assumed known, the proper distribution to use is the
Standard normal distribution
If a hypothesis test leads to the rejection of the null hypothesis, a
Type I error may have been committed
If the margin of error in an interval estimate of m is 4.6, the interval estimate equals
X bar plus or minus 4.6
Read the z statistic from the normal distribution table and circle the correct answer. A one-tailed test (upper tail) at a .123 level of significance; z =
[(1-0.123)*100)] = 87.7 = 1.16
Read the z statistics from the normal distribution table and circle the correct answer. A two-tailed test at a .0694 level of significance; z =
[(1-0.694)*100)] = -1.48 and 1.48
An interval estimate is used to estimate
a population parameter
A Type II error is committed when
a true alternative hypothesis is mistakenly rejected
As a general guideline, the research hypothesis should be stated as the
alternative hypothesis
If two independent large samples are taken from two populations, the sampling distribution of the difference between the two sample means
can be approximated by a normal distribution
For a two-tailed hypothesis test about m, we can use any of the following approaches except
compare the level of significance to the confidence coefficient
To compute the minimum sample size for an interval estimate of m, we must first determine all of the following except
degrees of freedom
For a two-tailed hypothesis test about a population mean, the null hypothesis can be rejected if the confidence interval
does not include m0
In order to determine whether or not the means of two populations are equal,
either a t test or an analysis of variance can be performed
For a one-tailed test (upper tail) with a sample size of 900, the null hypothesis will be rejected at the .05 level of significance if the test statistic is
greater than or equal to 1.645
A two-tailed test is a
hypothesis test in which rejection region is in both tails of the sampling distribution
A one-tailed test is a
hypothesis test in which rejection region is in one tail of the sampling distribution
If a hypothesis test has a Type I error probability of .05, that means
if the null hypothesis is true, it will be rejected 5% of the time
In testing for the equality of k population means, the number of treatments is
k
If the cost of a Type I error is high, a smaller value should be chosen for the
level of significance
The within-treatments estimate of o2 is called the
mean square due to error
For which of the following values of p is the value of p(1 - p) maximized?
p = 0.50
A p-value is the
probability, when the null hypothesis is true, of obtaining a sample result that is at least as unlikely as what is observed
From a population that is normally distributed with an unknown standard deviation, a sample of 25 elements is selected. For the interval estimation of m, the proper distribution to use is the
t distribution with 24 degrees of freedom
Independent simple random samples are taken to test the difference between the means of two populations whose variances are not known. The sample sizes are n 1 = 32 and n 2 = 40. The correct distribution to use is the
t distribution with 70 degrees of freedom
In hypothesis testing, the alternative hypothesis is
the hypothesis concluded to be true if the null hypothesis is rejected
In determining the sample size necessary to estimate a population proportion, which of the following information is not needed?
the mean of the population
In developing an interval estimate of the population mean, if the population standard deviation is unknown
the sample standard deviation and t distribution can be used
The t distribution should be used whenever
the sample standard deviation is used to estimate the population standard deviation
If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the
width of the confidence interval to increase
For a sample size of 30, changing from using the standard normal distribution to using the t distribution in a hypothesis test,
will result in the rejection region being smaller