Linear mixed effects models - random slopes and interactions | R and SPSS

1. Simple linear regression
2. Random intercepts (01:20)
3. R code with lme4 package (02:07)
4. Random intercepts and slopes (04:00)
5. Only random slopes (05:00)
6. Two factors with interaction (05:37)
7. Compare two models (08:55)
8. SPSS (09:52)

[prilolla]

This is the best video so far I have seen. We need people who can explain concepts in simple terms.

[Sam-tgii]

Your explanations are very clear. Thank you so much

[atkiltgg]

Excellent teacher! Thank you for all your efforts to make us understand it well! Well done!

[prilolla]

I really appreciate teachers like you with which we can understand the concepts and apply our research questions easily. I would request a video in detailing the difference between FE, RE, and ME. And also when to use these three models. Thanks you for your time.

[Grbec]

Best explanation on mixed-effects models on YouTube. Thank you for a great job!

[amywilderson]

I greatly appreciate it!! I have taken longitudinal courses but some of the concepts did not make sense to me. Now thanks to you I have a better vission of mixed effect models. (I am very grateful of you for teaching concepts with graphs)

[yonyc]

You are an excellent instructor!
Thank you very much for your content!!

[ghditnf]

What an expert you are ! If you add some examples with animated figure, then you would be a super star to the academic field, I am sure.

[iriizb]

Thank you so much. I appreciate your clear explanation and example code. Very helpful.

[MegaAvi]

Excellent video! Thank you.
Would you kindly clarify why you used the measure at time 0 as one of the repeated measures? Shouldn't the value at time 0 (pre-treatment) be considered a covariate and not one of the repeated measures (i.e., post-treatment outcome)?

[fishfeelpain]

Your videos are addictive! If you could do something about survival analysis that would be amazing, as there isn't much available yet on Youtube.

[momomo]

Thank you for such a great explanation!
Two questions:
1. Should weeks be continuous or a factor variable? I guess it depends on if you want overall effect, or effect from week to week? When doing factor, I get an error when including weeks as random slope, how can I fix this?
2. How about if we want to see if the change is different depending on gender? Could we write: weight ~ weeks*gender + (weeks | subjects)? I am confused since the gender is essentially included in subject, but I want to see if there is any difference in change over time

[Sam-tgii]

I have one question: this type of graph at 1:25 to visualize the effect of the clusters on the regression line is very helpful. But what if we have multiple independent variables. How can we visualize the regression line across the clusters?

[fazlfazl]

Am I right if I say that including WeeksxDiet allows for DietA and DietB to have different slopes i.e.Subject 1 and Subject2 will have the same slope but it will be different from the slope of Subject3 and Subject4 (which have same slope).

Further, in Weight ~ Weeks × Diet + (1 + Weeks|Subjects), including Weeks as a random effect will then allow all subjects to have uniques slopes which can be seen as a step further than just including WeeksxDiet but no random effect for Weeks?

[ast]

6:57 I don't understand how we can now assume that the Groups have one random intercept. That would mean each group has their own distribution, which is not the case because as you said all 4 subjects are randomly sampled out of one distribution.

[CanDoSo_org]

At 2:48, why I only got one intercept instead of multiple?

[SwavimanKumar]

I have seen examples like this, m <- mlogit(mode ~ price | income | catch, data = Fish). What does so many pipes mean here?

[dtxrxkr]

I really appreciate your clear explanation on the concept of linear mixed effects models. Could you or someone clarify which data format should be set for using lmer? I think 'long' format according to "weeks" would be appropriate. Right?

[gerardaristizabalpla]

Great video! By any chance do you have the R translated to Python codes?

[SIENEKEFTWLOL]

Excellent video. Do you know how to get SPSS to produce the individual slopes as a new parameter?