Main effects & interactions 

Funny that the example was sleep deprivation, because I fell asleep during the lectures on main effects and interactions and missed learning this. Thank you so much for helping me out!

amazing explanation, thanks boss

For a now retired but still active biomedical scientist this is the best explanation I've ever seen of main effects and interaction

The easiest to understand explanation of all the different videos i have looked at. Perfect! Thank you!

Oh my goodness! I finally get it! Thank you so much for making this topic so understandable.

After reading text books , reading so many articles and research paper and seeing many youtube videos I thought of giving up the topic but at last I found your video and it made the concept all clear. Thanks a lot from India for uploading such nice video on this complex topic.

This is a super helpful explanation to a relatively complex topic, it makes it seem very intuitive and I wanted to thank the author of this video

After a day of trying to figure this out in my textbook, I finally looked it up on RU-vid. You just resolved a days worth of stress. Fuck the textbook. I’m using RU-vid from now on.

Hi Jim, thank you for your simplified version of understanding fANOVA! Choosing the right statistical test gets quite difficult with many groups, and multi-dimensional output variables, this helped a lot!

Very helpful video. Thank you for taking the time to post it and make it public.

My lecturer would not stop going on tangents and then pausing only to attempt three more times to explain what these effects are. My test is tomorrow, you are a life saver. Thank you!

I go to school in the U.S. and was so confused learning about this, but this video helped me understand factorial designs better, thank you!

the vid my professor attached to teach us this cuz it's an online class is 2 hours long. You just summed up 2 hours, held my attention, and made it make sense. omg THANK YOU!!!!!! - a sleep deprived nursing student who's trying to self teach herself stats

Excellent video. Searching on RU-vid for the last hour or so for a clear explanation on the meaning of main effects and interaction and this video was the best by far.

This sleep deprived Tilburg University student thanks you very much! Great explanation and very useful for my research note.

This is the video that helped my brain wrap around the topic main effect and interaction. Thank very much !

holy cow, you made that so easy to understand! i can't believe none of my teachers could explain it so simply! thank you so much! research methods has been the bane of my existence because i just can't seem to process it!

THANK YOU THANK YOU THANK YOUUUUUUUUUUU!!! Sorry for the caps, but I've never seen SUCH A CLEAR explanation of this. THANK YOU!

Thank you this is so much more clear than the mess my lecturer left me with!!

Most useful exploration of this I have read or seen - thank you

Thank you so much for this! Just one thing regarding the interaction effect. When I saw a few graphs showing two variables that cross each other while both variables had the same level of gradient, I at first thought there was no interaction effect. Since yes, one variable rises while the other one falls, but both had the same level of gradient. But there is still an interaction effect, as I found out. So I personally find it easier to memorize that there's always an interaction effect as long as the two variables aren't parallel.

I am having my very last exam of my whole study in 2 hours and this topic was something I just could not wrap my head around. Now it finally make sense to me. (And it is so ironically that I am sleep deprived and only working on caffeine fuel). Thank you!

I'm currently in a research methods class and this video has really helped me figure out main effects. My teacher gave us an exam including main effects and didn't explain at all like you did. Thank you.

Been stuck on this in 2 days, this video cleared everything up. Thank you Jim!

Thank you Jim for this simple explanation about the two topics. At min. 6:30 (about interaction) I suggest to note the difference on 1h and 24h of caffeine on the percent correct/ y-line.. The difference of 10 (percent) is on the y-line/vertical line. Regards and keep this up!

Thank you so much Jim. That really made it clear. You have a superb way of explaining things.

Thank you very much for your explanation!!! This video really helps me understand better about main effects and interactions!!!

Oh my GOODNESS thank you so much for this. My discussion went over it so quickly I didn't catch any of it! Thank you a thousand times over

Most helpful. The best explanation I've seen on this. Thank you.

AMAZING VIDEO. you're saving lives, my friend!

Thank you for this video!!! I was tied up in knots over my main effects and interactions as there was significant main effects but not interactions. Made perfect sense. Funny how you can spend 3years at uni being lost in statistics, yet a simple video works wonders :-D Thank you!

This helped so much to see it in a real example. My lecturer showed them as A and B so I had no idea what was happening

Thank you! Such a great and clear explanation!

You have hit the bull's eye. Crystal clear explanation. Salute

Clear explanation. This helps me a lot! Thank you~~

best explanation on this topic .Thank you.

I have an exam tomorrow for my research methods class, thank you for this video!

This was a great explanation, especially describing how to interpret the line graph! Thanks!!

That was the best video about this topic. Thanks a lot!

Awesome job Jim! I only spent one whole week trying to understand anything at all about main and interaction effect, banging my head and hoping I could drill it in (thanks to a no-so-good UC Berkeley PhD psych teacher), and then you happened in my life!! (and this is a junior college psych class!!). Thank you!!!

Very simple to understand the complex concept, thank you very much

Thanks! You really helped me understand this better.

Great explanation. Thank you.

I'm not in your class but this is going to help me pass mine! Thanks Jim!

I'm not even from this uni and I wish you were one of my lectures 😔

I put this video in my pocket! Awesome and clearly to the point thank you!

Thanks for making it short, sweet, and to the point! I wish my minister would do the same in church!

This was super useful! Thanks a bunch!

This is so great! Thank you for providing this to your students and the rest of the students in need of an explanation.

this makes so much more sense now, thanks!

Really good explaining!

Thank you sir for making sense of this topic :)

Thank you from the University of Cape Town!

WISH YOU WERE MY LECTURER

Nice examples. Thanks.

best video on the subject

Thank you sooooo much for this video!! My GPA has been saved.

thank you - just completing the last assignment of my Research Methods in Education / online and this helped a lot Jim ! Cheers fro NZ :D

Thank you so much!!!! .You save my final examination's score!!!

Thank you! This made absolutely no sense before, and I just got a perfect score on a test after I listened to this! :)

Excellent video 🌟❤️

this was soo clear :)

excellent. well simplified. i have clearly understood

this was beautifully described and the example was easy to interpret! thanks!!

Thank you. I hink you only forgot to mention that if they will eventually INTERSECT on one end of the lines ( which in this case yes they will intersect on the upper left) meaning if we used a different amount of caffeine in the pill or had them skeep deprived less than 1 hour. No intersection = no interaction.

Thank you so much!!! I was really struggling with this concept and not being able to wrap my head around it.

having exam about these atm and its so great that i found this video, thank you so much mate :)

So clear to understand, thanks you so much!!!

Best explanation ever

Thank you!!! This was so helpful. Please keep posting videos!

Amazing video! Very well explained, thank you. Do you have another video where you explain how to test whether these effects are significant or not? Would be greatly appreciated!

AMAZING! Thank you so much for this!

Really great vid!!!

Very clear explanation--thanks, sir.

great explanation ,thank you

thank u Jim. A student from Greenwich university, this was VERY helpful!

This is great, it really helped me understand main effect and interaction. Thank you!

thanks for the simple clarification

Well explained, thanks!

Nice illustration mate!

Very helpful good teaching

Thank you very much Jim. It help me a great deal.

This was phenomenal. - Neuroscience Master's Student

I hope you all find this video useful! If you have any questions, please do drop me an email. And if the video has REALLY helped and you want to buy me a beer, please see www.paypal.com/donate/?hosted_button_id=L692FVF8PNUKU

Thanks for this video. It is easy to understand.

Thank you so much, this really explained things clearly.

Thank you very much Helped a lot!

A good way to describe the interaction in words: "The type of supplement given (caffeine or placebo) moderated the effects of sleep deprivation on memory recall (or whatever other dependent variable)." Correct me if I am wrong. I am in the process of trying to understand how to describe interactions in words, haha.

Very clear !!! Thanks 😊

This video helped clear things up. Thank you so much!

Thank you so much! You just saved me for finals :')! Please keep uploading, you explain things perfectly :D

Thank you so much Jim!

Thank you! This might have saved me

This was an awesome video, thank you for your help.

Thank you!!! This was very well explained & helped quite a lot

thank you SOOOO MUCH. I have a single course exam tomorrow, if i pass im gonna graduate. If i had money i would definitely buy a bottle of fine champagne but i dont :( I HOPE I PASS TOMORROW

this helped me so much!! thank you

yes jim mate sick vid helped me and my m8 a lot with some well hard stats work that she couldnt do safe again xx

much respect, i am now more prepared for my final tomorrow