Research Chapter 10
Write out, in words, a research hypothesis for this statement: The Geography Department is interested in finding out if the average GPA of this year's graduating seniors is comparable to the average GPA of graduating seniors over the last 40 years.
The average GPA of the Geography Department's current graduating seniors is not the same as the average GPA of the graduating seniors in the history of the department.
In the effect size formula, what does σ signify?
the population standard deviation
If you have a population standard deviation of 18 and a sample size of 81, what is your standard error of the mean?
2.0
In z = 2.56, p < 0.05, what is the obtained value?
2.56
If you have a population standard deviation of 18 and a sample size of 36, what is your standard error of the mean?
3.0
In the formula for calculating a z score, what does σsignify?
the population standard deviation
If the sample mean is 30, the population average is 10, and the standard error of the mean is 5, what is the observed z value?
4
If the sample mean is 20, the population average is 10, and the standard error of the mean is 2, what is the observed z value?
5
If you have a population standard deviation of 10 and a sample size of 4, what is your standard error of the mean?
5
If you have a population standard deviation of 18 and a sample size of 9, what is your standard error of the mean?
6
If you have a sample size of 4 and a population standard deviation of 12, what is your standard error of the mean?
6
How is the standard error of the mean calculated?
the population standard deviation divided by the square root of the size of the sample
In the formula for calculating standard error of the mean, what does n signify?
the sample size
The denominator in the equation for the z value is equal to ______.
the standard error of the mean
If the sample mean is 100, the population average is 90, and the standard error of the mean is 10, what is the observed z value?
1.0
If you have a population standard deviation of 9 and a sample size of 81, what is your standard error of the mean?
1.0
If you have a population standard deviation of 20 and a sample size of 4, what is your standard error of the mean?
10
If you have a sample size of 16 and a population standard deviation of 40, what is your standard error of the mean?
10
If the sample mean is 25, the population average is 5, and the standard error of the mean is 10, what is the observed z value?
2
With a sample mean of 10, a population average of 15, and a standard error of the mean of 10, calculate the observed z value.
-0.5
The sample mean is 12, the population average is 19, and the standard error of the mean is 4. What is the observed z value?
-1.75
You have a sample mean of 11, a population average of 17, and a standard error of the mean of 3. Calculate the observed z value.
-2.0
If our sample selection was perfect, what would be the difference between the sample and population averages?
0
The level of risk associated with the null hypothesis is generally set at ______.
0.05
Calculate the observed z value using a sample mean of 25, a population average of 20, and a standard error of the mean of 8.
0.63
What is the standard error of the mean when you have a population standard deviation of 2 and a sample size of 9?
0.67
If you have a population standard deviation of 7 and a sample size of 100, what is your standard error of the mean?
0.7
What is the standard error of the mean when you have a sample size of 144 and a population standard deviation of 9?
0.75
How many groups are compared in a one-sample Z-test?
1
If the population average is 45, the sample mean is 50, and the standard error of the mean is 5, what is the observed z value?
1
A value of 0.2 for the z value after conducting a one-sample Z test leads to which conclusion?
Accept the null hypothesis.
What is an example in which a one-sample Z test would be appropriate?
Any test in which the mean of a sample is compared with the mean of the population.
Dr. Meow teaches Engineering Science 101 and is interested in finding out whether her students perform better on math tests compared to all of the engineering students in the university. State this as a null hypothesis.
Dr. Meow's students do not perform better on math tests compared to all of the other engineering students.
Dr. Meow teaches Engineering Science 101 and is interested in finding out whether her students perform better on math tests compared to all of the engineering students in the university. State this as a research hypothesis.
Dr. Meow's students perform better on math tests compared to all of the other engineering students.
In the effect size formula, what does d signify?
Effect size
What is effect size?
Effect size is a measure of how different two groups are from one another—it's a measure of the magnitude of the treatment.
True/False: A one-sample Z-test can be used to compare the mean of two samples.
False
True/False: According to your text, there are five steps that you should follow in order to compute and interpret a Z-test statistic manually.
False
True/False: If you're comparing the test scores between two classrooms, you should use a one-sample Z-test.
False
True/False: SPSS does not offer a one-sample t-test.
False
True/False: Sample size is taken into account when computing effect size.
False
The null hypothesis in a one-sample Z-test would be represented as follows:
H0: = µ
Write the formula of the null hypothesis for the following research problem: The Geography Department is interested in finding out if the average GPA of this year's graduating seniors is comparable to the average GPA of graduating seniors over the last 40 years.
H0: = µ
An alternative hypothesis in a one-sample Z-test could be represented as follows:
H1: ≠ µ
Write the formula of a directional or nondirectional research hypothesis for the following research problem: The Geography Department is interested in finding out if the average GPA of this year's graduating seniors is comparable to the average GPA of graduating seniors over the last 40 years.
H1: ≠ µ or H2: > µ
Calculation of the one-sample Z-test gives you ______.
the obtained value
For the Z-test, the population's standard deviation is ______.
Known
SPSS does NOT offer which of the following?
One sample Z-test
After conducting a one-sample Z-test, you arrived at a value of -12.5 for the z value. What is your conclusion?
Reject the null hypothesis.
After conducting a one-sample Z-test, you arrived at a value of 5.7 for the z value. What is your conclusion?
Reject the null hypothesis.
If the obtained value is higher than the critical value, what is the conclusion?
Reject the null hypothesis.
In the formula for calculating a z score, what does μsignify?
the population average
Mr. Moo would like to find out if his daisies grow at a faster average rate than the average rate of daisy growth in his neighborhood. State this as a null hypothesis.
The average rate of growth for Mr. Moo's daisies is not significantly faster than the average rate of growth of daisies in the neighborhood.
Mr. Moo would like to find out if his daisies grow at a faster average rate than the average rate of daisy growth in his neighborhood. State this as a research hypothesis.
The average rate of growth for Mr. Moo's daisies is significantly faster than the average rate of growth of daisies in the neighborhood.
The numerator of the equation for the z value is ______.
the population average subtracted from the mean of the sample
In the effect size formula, what does X bar signify?
The sample mean
What are the guidelines in using effect size?
The small effect size ranges from 0 to 0.2; a medium effect size ranges from 0.2 to 0.8; and a large effect size is any value above.8.
In the statement z = 3.14, p < 0.05, which of the following interpretations is TRUE?
There is a significant difference between the sample value and the population.
In a t-test, if the resultant t value is -2.72 and p < 0.05, what is the interpretation?
There is a statistical significance in the test.
In a t-test, if the resultant t value is 2.72 and p < 0.05, what is the interpretation?
There is a statistical significance in the test.
In the statement, z = 1.42, p > 0.05, which of the following interpretations is TRUE?
There is not a significant difference between the sample value and the population.
True/False: A large effect size is any value above 0.8.
True
True/False: According to your text, there are eight steps that you should follow in order to compute and interpret a Z-test statistic manually.
True
True/False: Effect size is a measure of how different two groups are from one another.
True
True/False: SPSS does not offer a one-sample Z-test.
True
True/False: The results of both one-sample Z- and t-test are basically the same when the sample size is greater than 30.
True
In the effect size formula, what does μ signify?
the population mean
If the obtained value is NOT higher than the critical value, we ______.
accept the null hypothesis
The standard error of the mean is the best estimate that we can come up with given that it is impossible to compute ______.
all of the possible means
After the z value is calculated, locate the ______ from a table of z scores.
critical value
In interpreting effect size, what is the meaning of effect size at 0.8?
large effect size
The one-sample Z-test is used to compare the ______ to the ______.
mean of a sample; mean of a population
In interpreting effect size, what is the meaning of effect size at 0.4?
medium effect size
For the t-test, the population's standard deviation is ______.
not known
In z = 2.56, p < 0.05, what is the probability?
p < 0.05
The level of significance is determined by which of the following?
researchers
What is the meaning of an effect size at 0.2?
small effect size
What is the meaning of SEM in the formula for calculating a z score?
standard ease of the mean
The standard deviation of all possible means selected from the population is the ______.
standard error of the mean
What is the denominator in the equation for the z value in a one-sample Z-test?
standard error of the mean
