For our last HW, would it be possible that we get that before the middle of next week. So we can refer to it as we are doing our final project.

IF P is greater than .05, do we report in that case as P > .05

"on the margins"

What does it mean that outliers are examined "on the margins" and that Fmax is assessed "on the margins"? What are margins?

Independence of errors

What is independence of errors? Is this different than independence of observations?

front desk- attendance sheet

For those of you who are in the Monday-Wednesday class, please go to the front desk sometime between tomorrow and next week to sign the attendance sheet for this last Monday if you were in attendance. We forgot to send the attendance sheet around and want you to get credit for being present. Thanks!

If F is less than .01, how do we report that?

Section 8 of the Review Sheet

I asked Dr. Clements what you would need to understand about Section 8) "Know how models that mix random effects and fixed effects behave and how models that mix Repeated Measured and Randomized Groups behave. Understand the similarities and differences between such a mixed factorial model and a randomized effects factorial model."

She said something very similar to what TJ said in the review. Both random effects and repeated measures variables influence the whole model in that they change the way in which effects are tested. So if there is one random effect IV, it changes the way all IVs are evaluated (against what error term). Same goes for repeated measure.

You should be able to recognize whether there is either a repeated measure or a random effect from the data as opposed to analyses that don't include either.

Homework Question: Changing up Randomized and Fixed Effect Variables

So I said I would look at the homework and try to address the question about mixing randomized and fixed effects, but none of the questions I'm looking at on the homework seem to resonate with what we talked about in class. Can someone remind me which question you wanted discussed? Thanks!

Reporting Non-signficance

There was a question in class this morning about whether you have to report the inferential statistics for non-significant results in ANOVA. You do not need to report the inferential statistics for non-significant results. You can look at the example write-up on page 368 of the book for an example of a write-up that only reports the inferential statistics for significant results (specifically, they leave out the inferentials for some of the two-way interactions). However, you do need to indicate that the results were non-significant (they do this in the example by using phrases like "only for small cars was the interaction statistically significant").

For doing an F-max, how do you do that when you have two IV's?
Is it data, split file, organize, by group, and the two levels of IV.

In the final project, I am having a hard time with normality, my DV is not in a normal distribution would do I do in that case, also what if my Z is a negative.

here you guys I hope you find this helpful

Factorial ANOVA, Advantageous and Disadvantageous

Advantageous:

1. It tests for two or more IVs thus preventing an inflated Alpha that would occur if you run separate oneway ANOVAs

2. Allows for separate evaluations of each predictor variable.

3. Allows for examinations for Joint, or interactive effects of the variables.

Disadvantages:
1. Crossing multiple variables with many levels dramatically increases the resources required.

Repeated Measures

Advantageous:
1. Fewer participants are needed

2. Greater Familiarity with research procedure (Less time recruiting and explaining)
3. Each participant serves as own control

4. More power, since variance due to participant can thus be partialed out of error term.

Disadvantageous:
1. More is required of each participant

2. Sphericity

Mixed Designs

Advantageous:
1. Both combines randomized and repeated components.
2. Mixed Designs are preferable if carryover on one variable is a concern,
but change over time is of interest.

Disadvantageous:

1. The assumptions of Normality, homogeneity of variance, independence of observation and Sphericity are all in play.

ANCOVA
Advantageous:
1. Removes variance due to extraneous variable from error term
2. DV scores are reset to “what they would have been had all participants been equal on the covariate.”

Disadvantageous:

1. A causal relationship cannot be inferred especially if it is nonexperimental.

2. Very sensitive to outliers

3. Both covariate and DV have to meet normality

4. In nonexperimental designs, sometimes the covariate is substantively related to the IV.

5. Covariate only help if it is related to the DV, if not it just burned a degree of freedom for nothing.

6. A lot of assumptions, Multicollineratiy, linearity, homogeneity of regression, reliability of covariate, as well as independence of observation, normality, homogeneity of variance

Latin Square Designs

Advantageous:
1. Allow for incomplete crossover designs while maintaining the benefits of counterbalancing.

Disadvantageous:
1. Only a subset of possible orders is used.

2. You have to do it by hand.

3. It is hard to do and requires a lot of planning, ensuring that the orders and sequences are correct.

I hope this is not a lot to ask, but would it be feasible for us to get the grade for our last HW since it will aid us in determining how to do the final project and what mistakes to avoid?

In regards to the Final Project, I have sufficient subjects for both of my variables, however when I do a cross over between one level for example in gender with one level in something else, the N does not always turn out as 10. Is that a problem, should I find other variables?

In the random effects ANOVA, what does this statement mean "Population of levels is normally distributed with independent errors?

Missed class for Latin Squares!

Can someone answer these questions for me?

What would a significant main effect of order indicate in a Latin square design?

What would a significant main effect of sequence indicated in a Latin Square design?

What would a significant interaction of sequence and order indicate?

Random effects DF

Can someone list out the DF for the effect, interaction, and error terms of a random effects design?

Reliability of the covariate

Are you able to test for the reliability of the covariate in an ANCOVA? If so, how?

Descriptive and inferential stats

Are there different descriptive statistics required for different ANOVAs or do they all simply require the M, SD, and n?

In keeping with this, don't all ANOVA designs require df, p, F, and partial eta squared as inferential statistics? Do any designs require different inferential statistics?

Final Project

For the final project, do we have to use variables that measure psychological constructs or can they be unrelated to psychology?

Article Review 5

Hey my article review 5 has not been graded yet, does anyone know how long it will take to get that back?

When reviewing an article with a beta level, should I report to two decimal places even though the authors reported to three?

Screening Designs

What are these screening designs that the review sheet refers to?

Final Project

For the final project, are we supposed to use indepenent variables which yield significant results?  I ran an analysis which did not produce any significant results so I am wondering if I should choose other constructs.

review session

Sorry for the confusion about the review session today. If you have not picked up your review sheet yet, another TA, Eric, has them. We will be having a review session NEXT Tuesday from 1-2. As for how cumulative the exam is, study the review sheet, and that gives you specific things that you should know from past exams.

In the write ups, do we indicate that the IV is random or fixed?

Final Project

On TurnItIn.com, the final project only has one slot for turning it in. Are we only doing a write-up? Or are we combining the write-up and output?

Terminology

What is it called when we run, say, 3 factors that are random effects with 4 factors that are fixed? Do we call it a "mixed-model 3 x 4 factorial ANOVA" ?

Is it possible to have a significant main effect without a significant effect in post-hoc?

df for Random Effects ANOVA

Is it possible to get a df that's not an even number when doing a random effects ANOVA? For my random effects homework, I'm getting non-even number errof df, and a higher F but also higher p than for the fixed effects ANOVA. How is this possible?

Article Review: Relevance to Current Question

For the "Relevance to Current Question" section, the example article review only gives a very brief two-sentence description of how the article aligns with the author's interests and what future research could be done. Two times, I have got the comment that I need to flesh out this section. What more detail is needed in order to get full credit in this section?

On an earlier article review, one TA commented that numbers before measurements of time (e.g. years) are always put in number (e.g. 5) not word (e.g. five) format. Then on a later article review, I got a comment that numbers less than ten should always be put in word format, even for when describing number of years (e.g. one year instead of 1 year). Which is it? In the article I was reviewing, the author used the format "1 year."

Tables in ANCOVA homework

Should we be treating the one-way ANOVAs (in question 1 only) as two totally separate analyses and write ups, thus not needing a table for descriptives and just using them in text? Or should we be treating these as related ANOVAs in one writeup that should have descriptives identified in a table?

Independence of Observations

On the homework, for the ANCOVA, since it is a repeated measures design - they test people with a pre-test and then with a post-test, don't we automatically have a violation of the assumption of independence of observations?

Full ANCOVA Instructions

Moodle is having issues, and has overwritten the new ANCOVA directions with the old ones, even though the old file has been removed from the site. Not sure what is happening, but so that you get the correct instructions: ANCOVA Homework General Instructions 1. Answer the following questions in a Word document. 2. Do not include the questions in the document. 3. Number your answers. Analysis and Write Up Instructions 1. Using the dataset “new repeated measures and ancova,” run two separate oneway ANOVAs. In the first ANOVA, compare the intervention groups at pre. In the second, compare the intervention groups at post. Present your results in an APA formatted Results section. 2. Using the same dataset, run an ANCOVA examining intervention status on post scores, covarying out the effects of pre scores. Present your results in an APA formatted Results section. 3. Do you have concerns about homogeneity of variance in either of these analyses? Why or why not? 4. Do you have concerns about independence of observations in either of these analyses? Why or why not? 5. Do you have concerns about normality in either of these analyses? Why or why not? 6. Do you have concerns about multicollinearity in either of these analyses? Why or why not? 7. Do you have concerns about linearity in either of these analyses? Why or why not? 8. Do you have concerns about homogeneity of regression in either of these analyses? Why or why not? 9. (A) To what value of the covariate were scores adjusted? (B) What does it mean to adjust scores in this way? (C) Was this a reasonable value of the covariate for SPSS to use? Why or why not? 10. In your writeup of the oneway ANOVAs, did you use raw or adjusted means? Why? 11. In your writeup of the ANCOVA, did you use raw or adjusted means? Why? 12. Were post-hoc analyses necessary in either of these analyses? Why or why not? 13. What would be the key points in your discussion section, both about findings and about limitations? 14. Submit your printouts (making sure that the evidence needed to answer all questions is included) as a Word document to to turnitin.com. Submit your Word document with both, independent writeups (that is, treat them as if they were two separate results sections in two separate papers) to turnitin.com.

1. What does this mean? Please elaborate
   To what value of the covariate were scores adjusted? (B) What does it mean to adjust scores in this way? (C) Was this a reasonable value of the covariate for SPSS to use? Why or why not?
   

Question

I'm not sure I understand the question "Was this a reasonable value of the covariate for SPSS to use?" Is this because you want the mean of the covariate value to fall in between the means of the two levels of the IV?

Also, in regards to homogeneity of regression, is it possible to find you have/have not met the assumption without splitting files? By looking at beta scores?

ANOVA writeup

For the oneway ANOVAs portion of the homework, should we write a separate results section for each of the oneway ANOVAS or combine them into one larger results section?

Upcoming Review Sessions

The following review sessions have been scheduled. Tuesday, 11/15, from 1 to 2 p.m. Wednesday, 11/16, from 5 to 6 p.m. Tuesday, 11/22, from 1 to 2 p.m. Tuesday, 11/29, from 1 to 2 p.m. Wednesday, 11/30, from 5 to 6 p.m. All sessions are in Room 116. Attendance at any or all sessions is completely to your discretion. Come if you think it would be helpful. The first sessions will be student question driven. There will be no formal review sheet, so please come prepared with your questions.

how do we check for homogeneity of regression? Do we split the file and then do a one way ANOVA?

In regards to the HW, for the assumption of normality, do we do box plots to check for normality for each analysis, or do we just do a box plot testing the DV and CV?

HW grade change

My grade on my repeated measures homework was 93 last week (with the extra credit), now it is 77. Can someone please help me understand what happened? My pseudonym is New Pseudonym

Covariant & Indep

When covarying out pretest scores when looking at posttest scores, is independence of observation affected? Or does that only look at independence of observation between different participants?

submitting ANCOVA homework

In the ANCOVA homework instructions, it says to email the printouts. I am assuming this is incorrect, and I should just upload the output and write-up to TurnItIn.com like usual.

homogeneity of variance for CV

For ANCOVA, how do you test for homogeneity of variance for the CV (in addition to testing it for the DV)?

ANCOVA vrs Repeated Measures

When you could do either an ANCOVA or a Repeated Measures ANOVA with the variables you're looking at, what are the reasons to choose one over the other?

practice ANCOVA data set

What data set do we use for the practice ANCOVA homework?

Exam 2

Exam 2 is graded and at the front desk. As always, requests for assistance from the TAs should come to me via email. All questions about grades--homework or exam--should always come to me via email.

Dr. Clements, have you or the TA's gotten a chance to check my HW yetfor the wrongly deducted points? again my pseudonym is Kamel Tawadrous

Repeated HW

I also got points taken off for the mixed-designs portions of ALL the questions (2-8) the repeated measures homework (ex. #3 about homogeneity - the repeated portions answer was correct but the mixed designs portion of the answer was wrong so I got 0 points on the grading rubric rather than 10 points)! I know that I had the last 'discussion' question wrong, but I don't believe I got any other questions wrong for the repeated measures parts of the questions. Can you please also review my homework grading Dr. Clements? If the mixed designs portion of the homework was extra credit, I don't understand why we would get points deducted for getting answers incorrect. My pseudo name is ' New Pseudoname'

In regards to my repeated HW, I got points taken off for not including the post hoc which only applied to the mixed model design which was extra credit, also I lost points for not including a table for my mixed design. Can someone please explain to me what's happening?

Box's Test

Is the box's test only applicable to a mixed model design?

Trend-Analysis

I understand what a trend analysis is and what it tells us, but what does it have to do with sphericity. Why would we do a trend analysis if sphericity has been violated?

Extra Credit

For the repeated measures homework where we could get extra credit for attempting the mixed model questions, do the grades on turnitin.com reflect the extra credit, or is that our score without the extra points?

Is the Factorial Repeated Measures design is the same as the Mixed Design?

In regards to References, I feel like it is very vast to know all of it. Is there certain things we should be aware of as we study for it, like how you could use a quote as a reference, how to indicate if there is an anonymous author, etc.

Marginals

On the last slide of the Mixed Designs handout, it says that we can check normality of marginals for RM if df is low, and check if Fmax for the marginals is less than 10 in RM for homogeneity of variance. What does this mean? What are marginals in repeated measures and what do they have to do with normality or homogeneity of variance?

Also, how do we check an Fmax of less than 10 for marginals in repeated measures?

Can someone please specify the differences between Bonferroni, Scheffe, Tukey, Dunnette?

I know that Bonferroni, Scheffe, Tukey are all under homogenity of variance. Dunnette under heterogenity of variance.

Scheffe, Tukey and Dunnette, Equal cell sizes while Bonferroni has unequal cell sizes.

sphericity vrs. compound symmetry

What are the differences/similarities between sphericity and compound symmetry?

Invitation to an industrious student

Alright, so who wants to lay it all on the line and lay out the advantages/disadvantages/assumptions/when to use a RM ANOVA, a factorial RM ANOVA, and a MD ANOVA?

2 Questions: 1. Compound Symmetry 2. Post Hocs

1. In the mixed design, is Box's test of equality of covariance matrices what tests for compound symmetry? Or just part of compound symmetry? In repeated measures design, is compound symmetry covered by the test for sphericity (Mauchly's)?

2. In class, for post hocs for factorial design, we split the file and then looked at a post hoc run with a 1-way ANOVA, and for post hocs for mixed design, we split file, ran specifically chosen t tests, and then adjusted alpha. Why different post hocs approaches for the different types of designs?

degrees of freedom

For degrees of freedom in Repeated Measures, I am following what the handout says until the second to last bullet point where it says "degrees of freedom for the AS error term." What is "AS" referring to?

Exam

I was wondering what kind of references should we pay special attention to for the exam, should we mainly focus on referencing journal articles and books?