00:02 Understanding confounding and effect modulation in medical studies. 01:55 Understanding confounding vs. effect modulation 04:01 Smoking can affect the outcome, exposure, or both, impacting the study findings. 06:08 Confounding affects both exposure and outcome in research studies. 08:19 Understanding key methods for comparing means in research studies 10:11 Chi-square is used to compare proportional data 12:05 Understanding analysis of variance and t-tests 14:06 Understanding effect modulation vs. confounding 15:59 Understanding Number Needed to Treat (NNT) 17:38 Understanding of absolute reduction and number needed to treat 19:21 Effect modulation vs. confounding in research.

@RandyNeilMD

4 ай бұрын

Thank you...

@sahilgharde6407

4 ай бұрын

@@RandyNeilMD no problem sir

Man, these videos are gifts from the divine. Thank you, Dr. Neil!!

@RandyNeilMD

4 жыл бұрын

Sky, You are most welcome. Glad it was helpful.

Thanks, Dr. Neil for your dedication and help to all of us!

this is an amazing video! I kept getting these chi-square questions wrong over and over because I wanted to do it the "proper" school way. Dr. Randy you're a godsend! thank you thank you. Step 1 this Wed!

How is there not millions of views on this. I tried EVERYTHING to understand and remember biostats. THIS DID IT FINALLY.

@RandyNeilMD

2 жыл бұрын

Wohoo!! Perfection!!

Thank you, SIR!!!! future doctors owe it to you.

@RandyNeilMD

Жыл бұрын

Help the next guy in line...

Great, short and succinct. Thank you, Professor Neil! Amazing Video for Step 2 CK!

@RandyNeilMD

Жыл бұрын

You are welcome.

Dr. Neil is key to success. Thank you for everything you do and for posting these videos. No test prep company or any professor ever explained this to me. You are a true gift to the world. Thank you for sharing your knowledge.

@RandyNeilMD

3 жыл бұрын

Thank you for the kind words... KEEP MOVNG FORWARD. Keep me posted...

Dr. Neil these videos are amazing. Thanks for the great explanations!

@RandyNeilMD

3 жыл бұрын

Glad it was helpful.

Hi everyone, indeed dr randy neil did come down from heaven ! May God bless him on this Friday where ever he is now ...his unique flavor in teaching touched many dr's preparing for the usmle ...

@RandyNeilMD

Жыл бұрын

Thanks Jameel... Appreciate the kind words! KEEP STUDYING HARD!!

@jameelashkar9244

Жыл бұрын

By any chance , is it OK to share your email, any case any dr want to reach out and seek your advice on any matter relating to their journey!

@jameelashkar9244

Жыл бұрын

I will post my situation here , as I'm preparing for my usmle , I'm also applying for jobs in clinical research , residency is going be competitive, your thoughts dr randy neil is appreciated as always ...

@RandyNeilMD

Жыл бұрын

@@jameelashkar9244 sure... randy.neil8@gmail.com

Amazing video. Your dedication to medical field is greatly appropriated!

@RandyNeilMD

4 жыл бұрын

Princess, Thank you for the comment.

Thank you for being so thorough. Your work is amazing as expected 😉

@RandyNeilMD

4 жыл бұрын

Thanks Jolie, You are always very kind with your comments.

Great job Dr.Neil ,simply amazing.Huge respect for u

@RandyNeilMD

4 жыл бұрын

Mish, Thank you for the comment

Thank you so much. Tying to beat this beast of an exam is not easy, so these videos are a lifesaver!

@RandyNeilMD

3 жыл бұрын

Glad it has been helpful.

your videos have been so amazing thank you for your hard work! hoping you have time to upload a short one on population pyramid. happy holidays doctor Randy !

@RandyNeilMD

3 жыл бұрын

Michael. You are putting me to work...

Thank you so much another extraordinary video on biostatatistic, you are remarkable Dr.neil.

@RandyNeilMD

4 жыл бұрын

Musawair, Thank you for your support. Much appreciated.

This video is super helpful Dr Randy! Thank you so much.

@RandyNeilMD

3 жыл бұрын

Anusha, You are most welcome.

You are the best out there, Dr Neil. Stay awesome ⭐️

@RandyNeilMD

3 жыл бұрын

Thank you... I do appreciate the feedback.

I always watch your stats videos and genetics video before y FRCOPH exams. They are such immense help. I cant thank you enough. sending you lots of virtual flowers and wishes.

@RandyNeilMD

2 жыл бұрын

Thank you Kiva for the kind words.

Your amazing i feel so much confident about what I've learned , so very greatful.

@RandyNeilMD

3 жыл бұрын

Thank you for commenting

Thank you Dr Neil. Im in my first semester of my post grad studies Epidemiology and Biostatistics. Am currently learning Biostastics online (due to the pandemic) and it was just terrible. I couldn't nor understand grasp the calculation concepts at all. I came on KZread to look into Biostastics for dummies but came across your channels. Aren't I glad I did! I have been online all day going through your videos and I can say am confident that I can pass my biostat exams. Within a day am now very conversant with how to handle questions starting form the question part, before going through any long prose. I now know what formula to apply in a ,majority of the questions be it NNT, PPV, LR, AR%, when to draw the chi square among others. Thank you so so much. Your videos are extremely helpful. If you could do some videos on Correlation coefficients, confidence intervals and hypotheses, that would be great. So far, am grateful. I have a few questions to share with you for the purpose of helping me and the rest here learn better too. I'm not sure how to do so though. TIA

@RandyNeilMD

3 жыл бұрын

Clara, Glad it was helpful...

Thank you so much, Dr. Neil!

Gift from God. Thank you for making these concepts simple!!!

@RandyNeilMD

Жыл бұрын

Thank you for the kind words Yash

Thorough as always! Thank you!

@RandyNeilMD

3 жыл бұрын

Bork Boi, Thank you for your continued support.

Ur videos have been of great help to me in my biostatistics/epidemiology 👍

@RandyNeilMD

3 жыл бұрын

Ikechukwu, Thank you for taking time to comment. Glad it was helpful...

Thanks a lot Dr. Neil!! I am very much relieved now

@RandyNeilMD

2 жыл бұрын

Perfect.

Thanks Randy. Just to clarify (min 13:30): if the CI does not include zero is significant for a mean value. If CI does not include 1, is significant for OR or RR. : )

@user-nt1yw9cq3z

10 ай бұрын

This is exactly what confused me! Thanks for pointing it out. Aren't we talking about the RR here as well? So how do we day its significant even though it includes 1? 🤔

The best way in learning is to solve questions! Thanks for making it easy

@RandyNeilMD

2 жыл бұрын

Asmaa, Glad it was helpful.

Thanks Dr.Neil. I have tried alot sources but yours was best one.

@RandyNeilMD

Жыл бұрын

Thank you for the comment.... Glad it has been helpful.

hi dr. can you please do videos on... a. linear regression vs logistic regression b. kaplan meyer curve c. forest plot d. population pyramid p.s thankyou for your videos:)

@RandyNeilMD

3 жыл бұрын

Thanks for the topics... I will definitely look to see if I have those in the library... You are putting me to work.

@foodiexgamer9453

3 жыл бұрын

kzread.info/dash/bejne/p6CfwayQk86wZ5s.html

I needed this!!! Taking Step 1 soon and Im super nervous and anxious about it

@Michelle-fn5nc

4 жыл бұрын

Thank you for this videos!!

@RandyNeilMD

4 жыл бұрын

Michelle, You are nervous because it means something to you... STAY POSITIVE, STAY STRONG... Everything ha already been determined LONG AGO so NO NEED TO WORRY...

Dr Neil No words can describe about your teaching :)

@RandyNeilMD

4 жыл бұрын

Thank you Chetan... Hope you are staying focused and studying HARD!!

Thank you 😊.I was so confused about confounding,this was helpful.

@RandyNeilMD

4 ай бұрын

Glad it was helpful!

YOU'RE THE BEST! Thank you!

@RandyNeilMD

4 жыл бұрын

Thanks Ryan, Appreciate the comment.

Thank you Dr. Neil!

@RandyNeilMD

2 жыл бұрын

You are most welcome.

Fantastic video! Thank you!

@RandyNeilMD

3 жыл бұрын

You are most welcome.

Wow , great explanations and made so easy to understand the concept in ridiculously short time , Dear Dr kindly upload a Neuro video of high yield topics for step 1. Thanking you in anticipation 😊

@RandyNeilMD

3 жыл бұрын

Ahtesham, Thank you for commenting. I will eventually make my way to NEURO... I'll have to look back and see what I have. Appreciate the comment.

just found ur videos one month b4 my exam and stats were my weakest subject and its the oppsite now

@RandyNeilMD

Жыл бұрын

PERFECT!!

These are super clear to learn. Thank you very much

@RandyNeilMD

3 жыл бұрын

Chinthaka, You are most welcome.

Great video agan. Got a lot of these in the USMLEs

@RandyNeilMD

2 жыл бұрын

PERFECT. It WILL be out strength.

THANKYOU for another amazing video :)

@RandyNeilMD

4 жыл бұрын

Sarah, Thank you for the comment. You are most welcome.

These videos are awesome ❤️👏🏻 i just wanna ask u if we compare two mean values , when will it be regression analysis and when will be it two sample t test?? Because its so confusing

Awesome Dr Neil!

@RandyNeilMD

4 жыл бұрын

Thank you Obinna

Your videos should be an A plus resource for biostats in the First Aid section for biostats :)

@RandyNeilMD

3 жыл бұрын

Ali, Thank you for the kind words.

if only you would be teaching pharmacist for their board exam, they would have passed on a first try with flying scores. thank you for putting time and creating these videos to help us better understand confusing concepts .

@RandyNeilMD

3 жыл бұрын

Par Rez, Thank you for taking time to comment. I am humbled by your comments.

Sos un salvavidas, Dr Neil.

wow ! .. actually it should be woowooowoowooowooowo ! u made it like super easy within 22 min video ! I wana be your life long student , Sir . u r really great , hero of biostat I must say . i think everyone will agree with me too.

@RandyNeilMD

4 жыл бұрын

Taz, As long as we are all moving towards getting through these exams (STEP 1, 2, 3) then we will make whatever video topic is needed.

Thank u sooooo much .. no words 😶 to say....this is very very good....

@RandyNeilMD

4 жыл бұрын

USMLE Goal, Thank you for the comment

it was really helpful,thank you!

@RandyNeilMD

2 жыл бұрын

You are most welcome.

Thank you Dr. Neil

@RandyNeilMD

3 жыл бұрын

You are most welcome Amrinder.

This video saves my life. Thank you so much sir.

@RandyNeilMD

2 жыл бұрын

Glad it was helpful.

thanksssssssssss a TON dr Neil,

@RandyNeilMD

3 жыл бұрын

Syed, You are MOST welcome...

i dont understand the 2nd question on confounding and effect modulation. in the second half of the question statement where they corelated the effects of smoking with both alcohol consumption and pancreatic cancer the test results are of no significant value. both are more than acceptable 0.05. meaning that smoking is not related to either of them.

@arimetoprep1234

2 жыл бұрын

I have the same doubt

Nice concept explanation thank you

@RandyNeilMD

3 ай бұрын

You are welcome

Always hated biostats, was never any good at it. Thank you SO much for these simplified videos! Made it super easy! Can't thank you enough! I'm still can't get what's a good confidence interval value and why.

@RandyNeilMD

3 жыл бұрын

For the most part...think...the Confidence interval that doesn't contain the number "1" is good... 0.55-0.86 is good.... 1.2-3.5 is good... 0.9-1.1 is NO good...

@azzaamhyder4689

3 жыл бұрын

@@RandyNeilMD Oh okay, thanks alot!

A better explanation of chi squared would be that it's comparing two data sets where both the independent and dependent variable are categorical (vs categorical independents and measured dependent variables)

Hi Dr.Neil, can you do a video that involves the large 2 page pharm ads and how to navigate that? I get so intimidated. I'm trying to take the step III asap....my confidence needs the most work.

love every vid u made

@RandyNeilMD

3 жыл бұрын

Thank you for taking time to comment.

Thanks this is helpful

Thanks for the video. God bless you immensely. Please can you do a video on hazard ratio

@RandyNeilMD

4 жыл бұрын

Genesis, Thank you for the comment... Yeah, I should have put a question about HAZARD RATIO... let me see what i can find.

In the NNT problem, I believe you had labeled the graph correctly. If we are calculating EVENT RATE, then that means we are calculating who had hair loss in the control group minus who had hair loss in the treatment group. Please correct me if my concept is wrong though my step is in a few days LOL

@lifeandliving555

Жыл бұрын

I'm confused as well

@joshuawesley4727

Жыл бұрын

You are Correct👍🏼

@truthteller2711

11 ай бұрын

Legend

I know this is all for step 1 but I totally told my roommates who are taking step 3 now to watch these because they are struggling with biostats! I would totally add steps 2 & 3 in the title since this is just as applicable to them

@RandyNeilMD

3 жыл бұрын

Tina, Thanks for the confidence... I'm glad we can lessen the fear of Biostats... It should be one of those topics we can expect a good score.

@tinashealthbeautyworld8396

3 жыл бұрын

Randy Neil, MD for math lovers it is!! Haha But you have to keep in mind that not a lot of people love working with numbers! Personally, If I weren’t going to med school I’d be an Atomic Engineer because I love numbers and physics so much 😅

You are a blessing.🙏👏

@RandyNeilMD

6 ай бұрын

Thank you for the kind words.

Every video is so amazing 🔥🎉

@RandyNeilMD

2 жыл бұрын

Thank you WW

thankyouuuu dr Neil!!!

@RandyNeilMD

2 жыл бұрын

You are welcome Zuha.

Thank you so much, God bless you

@RandyNeilMD

Жыл бұрын

You are most welcome.

Thank you Dr. Please can you make quick vedio for the p value

Amazing! Thank you so much, specially the ANOVA, T test, and chi square!. I had a question about Q2 however; if they re-examnined the findings, and found that smoking/nonsmoking was only associated with a increase/decrease in smoking, wouldnt that be an effect modification as it only affects the outcome (of pancreatic cancer), and not the exposure (alcohol)? I am a little confused on that one

@RandyNeilMD

4 жыл бұрын

Saba, Thank you for the question... The take home point is that we know there is an association with BOTH exposure and outcome (for Confounding)...and only with OUTCOME for effect modulation. Everything else is "smoke and mirrors". Just take a step back and see it "big picture"... not sure if I am making sense...but for now, just know principle between the two.

@sabaali457

4 жыл бұрын

@@RandyNeilMD thank you!

Awesome!!

@RandyNeilMD

3 жыл бұрын

Thank you Suryasnata

Thanks always sir!

@RandyNeilMD

3 жыл бұрын

Appreciate your comments.

awesome simply awesome

@RandyNeilMD

Жыл бұрын

Thank you Simran.

First aid has NNT listed as NNT = 1/ ARR with ARR = (c/ (c + d)) - (a/ (a + b)). When I solved the problem using the formula from first aid, I got around 4.2 for my answer. I'm a bit confused on the formula you used to tackle the last problem.

Thank you so much 😊

@RandyNeilMD

2 жыл бұрын

Menekse, You are most welcome.

You are the best ❤

@RandyNeilMD

Жыл бұрын

Thank you

Hey Randy could you please explain relative risk reduction RRR=1-RR but I got lost with the words..can you just explain with an example?

Thank you 🙏

@RandyNeilMD

4 жыл бұрын

Sangay, You are most welcome. Hope you are studying HARD!!

Hi Dr. Neil. one more question : A 26 year old medical student comes to the physician with a 3 week history of night sweats and myalgias. During this time, he also had a 3.6 kg weight loss. He returned from a month tropical medicine rotation in Cambodia 1 month ago. A chest x ray shows reticulonodular opacities suggestive of TB. The student is curious about his likelihood of having active TB. He reads a study that compares sputum testing results between 2800 patients with likely active TB on a basis of history, clinical symptoms and CXR pattern and 2,400 controls. The results are: Active TB likely on basis of History, clinical and CXR Active TB not likely on basis of History, clinical and CXR Sputum Test positive 700 300 Sputum Test Negative 2100 2100 What is the probability that a patient with a diagnosis of active TB on the basis of history, clinical symptoms, and CXR pattern actually had active TB? The actual answer is 0.25. But my calculation is 0.70. Would you please explain this? Thank you

@BigGondi

3 жыл бұрын

Hi, the given table is the confusing aspect. They gave you the flipped table. The top heading should be the gold standard (Sputum test) and the side heading should be for the test conducted ( History, clinical and CXR) . You should rearrange and construct the chart like this: Sputum Test positive Sputum Test Negative Active TB likely on basis of History, clinical and CXR 700 2100 Active TB not likely on basis of History, clinical and CXR 300 2100 Then, PPV is 700/(700+2100) = .25

Thank you 🙏🏻

@RandyNeilMD

3 жыл бұрын

You are welcome.

Thank you so much..

@RandyNeilMD

2 жыл бұрын

Matanat, You are most welcome.

Hi Randy, great videos. In the second question I still don’t understand why smoking is a confounder bias rather than effect modulation.

@bronxbomma718

6 ай бұрын

Smoking affects exposure AND outcome (both of these variables) which is by definition CONFOUNDING BIAS. People who drink alcohol may also smoke (distorting exposure values) and people who smoke may also get pancreatic CA (distorting outcome values). This cumulatively distorts the relationship bridge between smoking and pancreatic CA and confounds the results. Smoking is an effect modulator with DVT as it only affects the outcome which is by definition EFFECT MODULATION. Think about it...smokers are vasculopaths who are inherently in a hypercoagulable state and thrombose easily) but there is NO clear association between the NMDA drug and smoking.

Very well explained

@RandyNeilMD

4 жыл бұрын

Shalvin, Thank you for the feedback... much apprecaited.

Hello Dr. Neil, I just discovered your amazing videos. I have some questions, is it possible to email you?

Thank you.

@RandyNeilMD

3 жыл бұрын

Hadeel, You are most welcome.

These videos should be on “Top videos” on KZread.

@RandyNeilMD

3 жыл бұрын

You are too kind...

Thank you

@RandyNeilMD

2 жыл бұрын

You are most welcome.

Thanks a alot for the video. If data is significant, can a question ask to choose between p value of 0.05 vs 0.03?

@RandyNeilMD

3 жыл бұрын

Only if they would say which was better... less chance for error... you'd choose 0.03

excellent

@RandyNeilMD

3 жыл бұрын

bbos, Glad it was helpful.

why for the last question when the equation was control - treatment, you put the new treatment data - the placebo ?

The table in the NNT calculation is flipped. Exposure(new med) should be at the left side(rows)

Randy you have great hands

@RandyNeilMD

3 жыл бұрын

I work out...

Thanks

@RandyNeilMD

3 жыл бұрын

You are welcome.

hello Dr.Randy Neil, how can I get notes for your stats lectures?

Hi Dr. Neil, thank you for the videos. Would you please explain this problem: A recent study was conducted to assess the intelligence of students enrolled in an alternative high school program. The results showed the IQs of the students distributed according to the normal curve, with a mean of 115 and a SD of 10. Based on this information it is most reasonable to conclude that a) 50% of the students will have the IQ below the standard mean of 100 b) 50% of the students will have the IQ below 105 c) Students with IQs of 125 are the 84th percentile d) 2.5% of the students will have IQs greater than 125 The answer is b. Would you please explain where did 84th percentile come from? Thank you!

@TheSomeGui

3 жыл бұрын

That is a rule of thumb: Mean +- 2SD = 95% confidence interval Mean +- 1SD = 66,6% CI In a Normal Distribution, mean = median = p50 An IQ of 125 is the mean + 1SD. So it is p50 + (66,6/2) = 83.3% (roughly 84%). We divide 66.6 by 2 because we are only adding 1SD, not adding and subtracting, get it? Remember: - 2SD = p5 - 1SD = p17 Mean = p50 + 1SD = p83 + 2SD = p95 + 3 SD = p99

Shouldn’t we put hair loss/ no hair loss on top of the chart and tx/no tx aside in NNT question? Thank you.

is there a mistake ? For the question with smoking and prostate ca, if the p values were not statistically significant due to the p-vaules doesn't it mean the results are not valid in the stratification and that there is NO difference, no effect mod, and No confounding? thx

@muhammadsuhaib2861

Ай бұрын

I was thinking the same that when one study is so statitically insignificant, how can we base our assumptions on that. Rather, it might be that the researcher had the predilection towards proving the association between the drug and DVTs, so he carried out an insignificant study to support his belief. In that case, the right answer would be 'confirmation bias'.

@muhammadsuhaib2861

Ай бұрын

You were probably talking about Q#2, but yeah same point in Q#1.

Hi Dr Neil, I have a question regarding Q2, in second part of the question the P value is high so wouldnt that means it is not significant and hence being a smoker or a non smoker doesnt really make a difference? am I missing out something here or am I not getting something and I have spoken something beyond stupidity? Would be nice if you shed a light on this. Thank you so much for your videos your work is wonderful!

@pawandeepkour544

Жыл бұрын

I have been having the same doubt. Hope Dr Neil replies!

I'm giving my Step 3 exam in 1 month!! I hope I pass!! I'll come back once i get my results.

@RandyNeilMD

2 жыл бұрын

STAY FOCUSED, STAY POSITIVE... YES, keep us posted.

So Randy if any time i see a confidence interval containing 0 decimals something i will cross that CI because of no significance?

Hey Randy! Which textbook do I use for bio stats ? Thank you

@RandyNeilMD

2 жыл бұрын

Arimeto, Not sure I know of one...

if u teach me rocket science,i would be a NASA scientist no doubt,take love from Bangladesh 💞

@RandyNeilMD

2 жыл бұрын

Thank you for the vote of confidence... I believe that if you learn something as though you were going to teach it to the next guy... we will learn much easier... My mentor was from Bangladesh...without her, I would not have succeeded.