Question

Week 8 Discussion

Consider the different post hoc tests discussed in the readings and respond to the following:

Describe the general rationale behind using post hoc tests (i.e., when they are used and why).

One of the advantages of using an ANOVA (compared to using
*t*-tests) is also a disadvantage—using an ANOVA makes it
necessary to use post hoc tests if there is a significant main
effect. We use a post hoc test because there is one specific
advantage in using an ANOVA. Explain why using an ANOVA naturally
leads to the need to have post hoc tests (hint: consider what you
are examining when you conduct a post hoc analysis).

Conducting a post hoc test is similar to conducting multiple
*t*-tests. As a result, it would seem natural to want to
bypass the ANOVA and just use repeated *t*-tests. Explain
why this approach is not necessarily a good idea and why an ANOVA
followed by a post hoc analysis is beneficial.

Describe an experimental hypothesis and explain which post hoc test you would use if you find a significant overall effect. Include in your explanation the pros and cons of each test in making your decision.

Answer #1

ANOVA is used to test whether the means of more than two groups are significantly different.

When we observe a significant difference in the groups, we use post hoc test.

The post hoc tests the pair wise comparison and let us know between which groups, the significant difference occurs.

The three main Post-Hoc tests are:

(i) LSD test.

(ii) Tukey’s HSD test.

(iii) Scheffe’s test.

Multiple t-tests would consume much time. However, ANOVA will compares together easily in one step and Pos-Hoc would help us to find the difference in the group.

1. What are the differences between planned contrasts (or
planned comparisons) and post hoc tests? Why are they used after
performing a one-way ANOVA? How do you decide which to use of the
two types of follow-up tests?
2. What are the main differences between between- and
within-groups one-way ANOVAs? What determines which type of test
should be used? Which is a stronger test and why?

The pairwise post hoc tests indicate which quality groups' means
are statistically significantly different for the others. Using the
results of the Tukey HSD post hoc test, what two quality rating
groups had significantly different mean alcohol by volume levels?
How do you know?
Post Hoc Tests
Multiple
Comparisons
Dependent Variable: Alcohol by Volume (in %) for
brand
Tukey HSD
(I) Rated Quality of
Brand
(J) Rated Quality of
Brand
Mean Difference
(I-J)
Std. Error
Sig.
VeryGood
Good
.30000
.12995...

Effect Size and Post-Hoc Tests
For each of the following studies, use the information given to
calculate the effect size and then do post-hoc tests and interpret
the results. Use alpha = .05
1. Fifteen third-grade students participated in a memory
experiment. Five students had a story read to them by a teacher,
five read the story themselves, and five saw a video of the story.
Each student then took a memory test on 12 items from the story.
The...

consider the data of pretest and post test scores
X1 (pre) X2(post)
2 5
3 7
6 11
5 9
perform a related-samples t-test on above data. a)
Conducting a two tailed
hypothesis test at the alpha = 0.01 what is the critical t
value?
b) what is the obtained t value that you
calculated from the above dataset?
c) given the obtained t and critical t
values, is the mean of the difference scores statistically
significant why...

8) Arnold compares the means of three groups and calculates a
value of -2.01 for the F ratio. This necessarily implies that. .
Group of answer choices
a. the mean of the first group is the highest of the three
groups
b. the mean of the third group is the highest of the three
groups
c. the differences between the means are statistically
significant
d. he made an error is his calculation
9) The problem with conducting multiple t-tests instead...

Please write in bold letters and number each
one
THANK YOU :)
Lesson Twelve you've seen how to use F-Tests and
Analysis of Variance to answer research questions relevant to those
statistical analysis procedures. Respond to the following to
demonstrate your grasp of these.
1. Describe a scenario where a
researcher could use an F-test for the equality of two
variances to answer a research question. Fully describe the
scenario and the variables involved and explain the rationale for
your...

For this discussion forum, refer to the Excel file
Discussion 8-1 Data Set that contains information on the
following:
In the healthcare profession, you will be presented with
ANOVA tables using different forms of technology
(i.e. SPSS, Minitab, Excel, SAS, etc.). An important part of the
analysis is to take the results from the ANOVA and make the proper
inferences from it.
Identify the worksheet (tab) that matches the first
letter of your LAST name (i.e., if your last name...

question 1
1)
Consider a significance test for a null hypothesis versus a
two-sided alternative. State all values of a standard normal test
statistic z that will give a result significant at the 10%
level but not at the 5% level of significance. (Sec. 6.2)
You perform 1,000 significance tests using α = 0.01.
Assuming that all the null hypotheses are true, how many of the
test results would you expect to be statistically significant?
Explain your answer. (Sec. 6.3)...

Review the Learning Resources and the media programs related to
t tests.
Using the SPSS software, open the High School Longitudinal
Study dataset found in this week’s Learning Resources and construct
a research question that involves a comparison of a means
test.
By Day 3
Use SPSS to answer the research question you constructed and
post your response to the following:
What is your research question?
What is the null hypothesis for your question?
What research design would align with...

*Requires SPSS Output for Graph, Descriptive table, Test of
Sphericity, Tests of Within-Subjects Effects, and the appropriate
post-hoc tests (pairwise comparisons) using a Bonferroni
correction:
Western people can become obsessed with body weight and diets,
and because the media are insistent on ramming ridiculous images of
muscular celebrities down into our eyes and brainwashing us into
believing these bulked of cross-fit types are actually attractive,
we all end up terribly depressed that we're not perfect. This gives
the evil corporate...

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