Biostatistics SUMMARY STEP 1 - USMLE The Extra stuff
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- Опубликовано: 26 сен 2024
- ESSENTIAL MATERIALS FOR USMLE STEP 1, 2CK, & 3 JOURNEY
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This is the second video summarizing the material for USMLE Biostatistics Step 1. Reviews NNT, NNH, ARR, ARP, Liklihood ratios, Hardy Weinberg. Good luck with Exam...
Feel free to email me at randy.neil8@gmail.com for notes or you can go to www.coastalmdl... to download.
Randy Neil, MD
INCREDIBLE VIDEO!!! Guys, listen up -- for my Step 1, Dr. Neil's videos were an absolute MUST. They single handedly got me through Biostats. You all NEED to watch the full set of his videos explaining the high yield principles that they're (likely) going to test you on. It's all HIGHHHHHHH YIELDDDDDDDDD
Thanks for the comment... Glad this stuff is useful for you.
DirtyUSMLE omg DirtyUSMLE you're here too? I love your videos too. Uhhhh doctors all around me. I'm in good company. Step 1 made easy!!!!!
Ok as you say Dirty, I trust you
OK my two fav RUclips med school profs
best anime crossover ever
the Husain Sattar of Biostats, absolutely incredible
Now I know the video is useful with that comment... Now I will be looking at his website calling him "Randy Neil of pathology"... appreciate the feedback
24:00 although it yielded the right answer i think theres a mishap in solving this. Because--
we first calculate whats the chance of a healthy new donor. Thats 2q = 1/150. (Because q=1/300)
Now that healthy donor passing the recessive allele is another 1/2
chance from mom is 1/2
so 1/2 x 1/150 x 1/2 = 1/600. thats the proper way of solving.
Thank you for thissss comment I have been looking for!
Hello thnku for ur comment, but can u explain y u did 2q? thats the part i coudnt understand.
@@mrinalinibuddha9033 q is diseased allele frequency. Now the sperm donor must be heterozygous normal if he is healthy phenotypically but still carry a copy of diseased allele. From the equation the heterozygous carrier frequency is 2pq. In these types of autosomal recessive diseases, they say that we should always consider "p" in 2pq as "1".
So 2pq = 2 x 1 x 1/300 = 1/150
That means that the sperm donor's chance of being a heterozygous carrier is actually 1 in 150, not 300, because he only has to have 1 copy of diseased allele.
1/300 just mean that in a pool of 90,000 people's chromosomes, 1 in every 300 copies is a diseased copy.
The rest is just like explained on above comment.
@@banya159thx u so much
@@banya159 You're amazing. Thank you for this thorough explanation! I understand now.
where were u in my entire life , it is people like u who make this world a much better place
Thanks for comment. Glad it was helpful
can you do some ethics review please ?
ur like a god at biostats
Watched these videos the night before each STEP and it saves me every time. Got STEP 3 tomorrow and cannot wait to be done for good. Thanks for the free points Dr. Neil!
How was it!? I'm taking it this Thursday, scared to death
@@scarlettflaz7304 How was it?
Amazing videos Dr. Neil. You're amazing! I'd like to add a little trick to memorizing the +LR and -LR; Positive has P and sPecificity has P; Negative has N same as SeNsitivity and now you can remember which one to detract from 1. :D Once again, Thank you soooo much. You're a life saver.
Sahand, that’s a nice way to memorize... -LR, +LR... works every time as we say...
Sir, I have been following your videos since medical school. They helped me pass step 1-3, and lastly the ABFM. I am now a board certified Family Medicine doctor. Thank you God, and thank you sir for these wonderful videos you provide for us learners. Thank you for everything and have a wonderful day.
Thank you for the kind words... I appreciate you taking time to check in. Such a long journey, but so well worth it!! CONGRATULATIONS!! Stay in touch...!!
Life becomes easier when there are teachers like you. God bless you.
Haroon, Thanks for the kind comment. Goodluck on STEP1
AND YO BOY is back for family medicine board certification studying. Thanks again!
One more test to go... CRUSH IT!!
Great video! Simple way of remembering which likelihood ratio has the [1- ] in it is the NEGATIVE likelihood ratio has the [1-] in the NUMERATOR. N=N. Just thought I'd share. Good luck all.
or (N)egative LR has "1- in front of the Se(N)sitivity", whereas (P)ositive LR has "1- in front of S(P)ecificity"
u think i know what a numerator is?!
Dr. Neil is the best. 1) these videos are succinct and clear 2) if you email him he will happily share his awesome notes and he responds super quickly! 3) he cares enough to share his knowledge and answer questions for tons of strangers. Thank you Dr. Neil!!!
The best explanations ever, you can read and learn for hours in Kaplan books and lectures and never get it, with your two videos I got it all. Thank you.
Okil, Thank you for the feedback
6 people disliked it, they prob found this video after taking the exam.
Thanks, no worries... Glad you found it helpful
Randy Neil, MD Honestly, I'been getting all of my U.W biostat questions correct just because of your videos. Thank you
😂😂😂
LOL!!!
😁😁
The extraordinary USMLE channel for Behavioral & Biostatistics 👍👍👍
Thank you Princess Z... as always.
i think these videos are by far the most underrated video for usmle prep
Im in med school now and I think I love you ❤ Excellent videos. Not enough praise can be given. Found you through Dirty medicine who I also love.
Ha... Appreciate the kind words
The fact that dirtyUSMLE is here and uses this proves the power of Randy Neil has to overcome Stats. Thank you both!!
This is my first ever comment on youtube but these videos have been so helpful that I can't thank Dr. Neil enough. Not only are his videos amazing, but he also personally emailed me the page of notes within hours of me asking. I always thought I was bad at math but with just watching his videos one time, I was able to do very well on my class exams and i even became a TA for biostats! What makes his teaching so crucially different is the fact that he provides detailed explanations for the "simple" math after knowing which equation to use. It's simple if you have a system and he provides you that logical system you can use each time. Almost all other professors and videos speed through this part and skip steps. Thank you so much! If only we had him for he rest of the math then perhaps I could also become an expert cardio, renal, resp, and pharm calculations. #thedream
these 2 videos are all anyone needs for step 1 bio stats, give ‘em a couple of watches before your exam and you’re good to go.
Appreciate the vote of confidence...
Dear respected Dr. Neil.
I cannot thank you enough for the very informative videos, and for your great kindness when I had the opportunity to communicate with you.
Thank you so much. God bless you and your loved ones.
Tawfik, Thanks for the feedback. Goodluck on the exam
AMAZING!! please please it's a MUST watch video if you are stuck with the concepts of Biostatistics for step 1.
Thanks for sharing such an amazing video.
Rabiha, Thank you for the kind words and taking time to comment.
I almost cried when you explained Hardy weinberg.
just found a new way to consume these great videos and would like to share it with yall: keep the video paused and try to solve the questions on ur own first - if u get stuck, play the video... its kinda like doing UWorld but the explanations are in video form and infinitely better :) and of course without saying... i never skip ads on these videos :)
Thank you Jerome for taking time to comment.
My dude is solving and correcting questions at the same time. 👍
Thats how we roll... :). Thanks for commenting
God bless you Dr. Neil, thank you for helping us with your educational skills!
It's my pleasure...
Thank you very much for these videos! Especially the setup for test day at the end is especially helpful.
Pavranium, Thank you for taking time yo comment.
I never even wanted to touch Boistatistics portion and thn one day i found your videos. God Bless u brother there isnt a better way to explain these topics. Thank you so much
Thank you so much for your videos and for understanding that we don't need to be 'biostatisticians' at this point ! very helpful .
Doctor Randy these lectures are on another level. we need content for step 2ck is a must.. seeing it in 2021
I'm trying to evolve into that...just need more time.
1/2)First of all no matter how much i thank you it's not enough, I'm forever indebted to you for your services sir.
Literally was pissed off as there were hardly 5-6 biostatistics qs in my exam 2days back.
Glad you crushed it though...
Where have your videos been all my life?Biostats has always been my weakest area, but these tricks are STICKING! For context I’m taking Step 3 tomorrow. Thank you!!
Better late than never. Crush it tomorrow. Stay confident.
@@RandyNeilMD My score came back and I am so happy with the results! These methods came in clutch, I don’t think I missed any of the biostats questions
This is the absolute greatest USMLE step 1 video on youtube.
Thanks for the feedback
FANTASTIC Way of seamlessly simplifying the material and explaining it in a easily re-callable way. Thank you SO much for posting these.
I like how you showed us at the end how you'd handle STEP1. Excellent leading by example!
Glad it was helpful...
Thank you so much Dr. Randy! Love how you made this available for free for us broke med students! Keep up the great work. Thank you for the notes :)
Get thru the STEPs and hopefully you won't be broke forever
@@RandyNeilMD you are the best !!
Your videos should be included in FA’s section of High Yield Resources.
Absolute absolute boon to mankind.
Wow. Thank youu sooooo much for all the videos Dr. Neil.
high yield for Step 2Ck as well; thank you doc.
I understood hardy weinberg principle for the first time ever . Thank you sir for making it so clear .
I honestly haven't missed a Biostat question since watching these videos. I am due to take STEP this June and this is hands down the best Biostat teaching I've received. Thank you so much for these videos. I've shared with all my fellow students and blew their minds as well! I review the material on my own and then watch these videos after and it solidifies the understanding. MUST WATCH for all med students!!! Thanks again Dr. Neil!
Thanks for comment
I cant thank you enough, your videos helped me a lot in step1 and hopefully in 2 as well.Regarding the UTI and the ABC drug group question , you are given the AR and incidence of standard therapy so Incidence of exposed to the drug will be incidence of standard - AR hence 2% then instead of doing all the RR calculation if you know that if 2%of the ABC group is 29 how much will 100% be so 100*29 /2. Same thing actually but is much faster in the exam.
exactly , that's what i thought too
It is incredible how in less than 30 minutes everything can make so much sense! Im in shock. Where have you been my entire life?! hahaha Thank you so so so much!
Funny... I'll take it as a good compliment. Confidence is key to the STEPs. Keep moving forward...
NOTE: the first NNT problem in this video is similar to the one starting at 13:20, however, in the first problem, they had already given you the “Event Rates” in the problem so you simply subtracted Event rates in control from event rates in treated to find ARR. vs. In other problem however, you had to find the rates (%) using the elaborated ARR formula (I.e. c/c+d - a/a+b). Not sure if I am 100% correct here, but that is how I understood it. Happy to be corrected.
yes, you are absolutely correct.
Thank you coz I was confused for a minute
I am pretty confused with the first question. The formula is event control rate - treatment. Which means placebo is the control which is 35 and treatment 60. So it was supposed to be 35-60= -25. I don't understand why he switched
@@kellyagyingi3412 did you get the ans why he switched im confused at same
Wish I found these last year for Step 1. But thankfully I found them before Step 2!!! Bless you
Thank you dr Randy Neil, step 1 on Tuesday now writing down all these formulas so that i can cram and write it down on my step 1 cheat sheet.
You will crush it... When you see BIOSTATS on your exam.. you will smile.
wow my STEP 1 is tomorrow and glad I ran into this!
what did you get on step 1?
Never understood epi/biostat until today thanks to your videos... I want my thousands of dollars wasted in med school to learn this subject back 🤦♀️.
Thank you again Sir.
Hors, Glad you found it helpful... Thank you for commenting.
@@RandyNeilMD About to take Step 2 and here I am again for a quick review... your videos are forever the best Dr Neil :D
Omg it is the best video on biostats ever. I have done kaplan qbabk uworld qbank and resource review and this video covers ALL the material
u are the best Randy and savior for biostats , never expected that biostats can be so easy!!
Glad it was helpful
Dr. Neil I don't even know how to begin to thank you. I had no idea what in the world I was doing on the biostats questions until I watched your videos. I have my exam next week and you're videos are gonna help make the difference. Thank you so much!!!
this is the best biostats teaching video! (along with part I of this series) Thank you SO much!
where is part 1?
omg!! thank you so much! the other older vids u made were gold but were way too basic for the current problems. biostats is def harder now on the exam thanks for making this I only get it when u explain it!
Agreed...the entire STEP 1 exam is a mindbender
This was an awesome video!! Explanations were perfect and so clear!! Thanks a ton!! Do you have a video on Chi Square, ANOVA, and T-Test by chance?
Omg I’m sooo thankful with you and your video this really help me to finally understand a better way to approach the statistics questions thanks a lot
For the hardy weignberg question with 25 year old, dont you also have to equate the chances of that healthy father giving that recessive allele to the child which would make it 1/1200 ? Thank you for the vids I recently had a uwolrd Q exeactly like that one.
this is so amazing, DR Neil yo the best teacher ever..... May God bless you for teaching the children of this world
Thanks for comment
Really appreciate your help, so efficient!
Glad it was helpful.
@Randy Neil, MD
For the first problem, to calculate ARR = ( % risk in control group - % risk in treatment group). You did mention that...but in calculation you did subtraction of 60 (Treatment X) - 35 (placebo). Is it absolute value over there? Because my answer for ARR is coming as -25%.
Usually in the control group the numbers of disease is higher compared to disease in treatment group and that would yield a positive number. He didn’t use the number like that - that’s why it’s a negative answer so ignore the negative sign and just pay attention to the concept being tested
I have been studying bio statistics for more than 3 days now and couldn't understand anything.
i watched your videos once and boom i am in the game now ;)
mother 1/2×1/2 ×( father or donor it is going to be 1/2 × 2pq q=1/300 q is iqual 1 by consensus in usmle so 1/2×2×1×1/300=1/300) then mother 1/4 × father 1/300=1/1200
I am astonished by the way you have explained biostats in lucid manner..
I incidentally came across your video while I was struggling with stats...This is superb.
God bless u Sir , I am so happy to fund u ,I didn't know how could study this material to hard for me , but u in only few hours explaining all ,
Dr. Neil's Biostats videos have been one of my most important resources for step! Thank you for making things so simple for us to understand Dr. Neil!
great video! quick correction though, i noticed for the second hardy-weinberg question, The Allele frequency was 1/300, you didn't calculate the Carrier Frequency, which should be 1/150 then you could multiply by 1/2 to get 1/300.. I think you skipped that part! Thanks for your awesome videos.
I was looking for the missing step thank you. That part didn't make sense alone for me.
I agree that he needed to calculate the carrier frequency for the dad drawn from the general population thus 2pq= 1/150. However, because the mom already is a proven carrier since she had an affected child, the probability that she is a carrier is 100%, or 1. The probability that the child will be affected by 2 carrier parents is 1/4. Thus the formula should be 1/150 x 1 x 1/4= 1/600
Wow this video was amazing. Especially I would like to give a special thanks to @Russell Leong for without your clarification I truly would have been lost regarding this confusion. I was wondering, are you single?
I guess that would depend on your genetics
But the question says ''Healthy Sperm Donor '', wouldn't that mean that dad has to be a carrier heterozygous only ? Thus, we will only calculate 2pq ?
God bless you. You make it so easy . A million thanks.
You are most welcome.
Here I am back for step 2 CK studying!
Crush it!
@@RandyNeilMD Here I am again x3 back for Step 3 studying lol!!!
@@myszkaJagi The good new is that BIOSTATS is only on day 1... well atleast that's how my exam was. The one area that I don't have any solution for is the "drug ads"... However, if you know the two summary videos like you did for previous STEPs you will do well. Good Luck. One step closer to the end!!
By far the best explanations for biostats and HW! Thank you so so much- your students are lucky to have you!
Thanks Kate... glad you found info helpful
Even after years he is generous enough to reply me asap and mailed me his notes.
Thank you so much for making these videos. They’ve helped me a lot❤️ . I was feeling so lost with statistics
Thank you Racquille for the kind comment.
The second question on Hardy-Weinberg needs revisit. The answer is 1/600 but our approach needs discussion. The women is receiving sperms from a health donor and NOT a diseased. So we should calculate pq. Incidentally, because the disease is rare (p approximates 1) pq is half of q ie 1/150. Again probability of pq impregnating with q allele is 1/2. So the chances of next baby suffering from disease are 1/2x1/2x1/150=1/600.
Q1) 0.39 seconds:
NNT or NNH : 1/ARR
1.01 seconds
ARR = |Ec- Et|
Q2) positive likelihood ratio @ 3.19 important for all the steps
PLR: sensitivity/ 1- specificity
NLR: 1- sensitivity/specificity
Q3) time stamp at 5:40
6:20 : the only questions asking to find % on step exam is ATTRIBUTABLE RISK PERCENTAGE, none else.
formula= RR-1/RR
Q4)7:30: how to differentiate lead time vs length time bias?
Lead time is detecting early
Length time is benign slow growin cases
Hawthorne: people under observation change their behaviour
Sampling: will this experiment on hispanic population work on other Eg Indians
Q5) 9:32 how to work reverses when ARR is given to find no of participants in the experimental group?
ARR = | Ec-Et |
Note: event means incidence
Q6) 13:30
Number needed to treat = 1/ ARR
Where ARR = | Ec-Et |
Q7)16:00 hardy Weinberg
Q8) 21.04
What’s the chance that MY SECOND child will have a rare AR?
24:08 cheat sheet formula revision
Thanks a lot! I have never seen anything as useful as this in my life. Wish you all the bests~!
I come back and rewatch this video before evey exam
On the one with Hardy Weinberg and an Autosomal Recessive disease.. the answer should've been 1/1200
from HW equation we figure it out that the probability that the sperm donor is a carrier is 1/300. the fact that mother has 1/2 chance of passing defective gene to the offspring. and the new sperm donor also has 1/2 chance of passing the defective gene. The equation works out as : 1/300 X 1/2 X 1/2 = 1/1200
Not quite. The allele frequency is 1/300, which means the probably that the sperm donor is a carrier is 1/300 * 2 (~2pq) = 1/150. Then we can take 1/150 * 1/2 = 1/300 for the sperm donor. Combine that with mom's 1/2 and we get 1/600.
My shortcut is this: The allele frequency = 1/300, which is the chance that the sperm donor's allele is q. (Remember, the donor's only giving one sperm; we don't have to evaluate his genotype, strictly speaking)
for the question about the possibility of the second baby having the ABC disease, wouldn't we also multiply the sperm frequency by 1/2 as well (just like we did with the mother) since he( the sperm donor) would be carrying the recessive allele on one chromosome because he is healthy.
Here I am Teacher watching you for the STEP 2 CK.... Thnaks
Angel, one step closer... It will work for Step 3 as well.... :)
best video for LR formula!!! It works
Eduardo, I'm glad it was helpful.
The easiest way of learning the whole statistics process and formula👌👌💐💐 thank you so very much 🙏🙏🙏💐💐
Thank you for the comment... Glad it was helpful.
Im going to pursue my PhD in Epidemiology and this videos are really helping me with Biostatistics concept.
Glad it has been helpful.
omgosh~ how do you do it, dr neil!! I tried to memorize the formula didn't work.. just watching you.. got me easy points. You are the best!!!!! WOW!!
Samuel, Glad it was helpful. Kick butt on the exam!!
Ohh bless you for adding Hardy- Weinberg
Came back for Step 2. Have it in 3 days. Getting me my extra points, thanks so much.
You will do well...no worries
It maybe inappropriate. But, can I say I love you? You made my day 100% better with the explanations. I will get back after test day!
Well, it's so much better than saying you hate me...so I'll take it. Keep me posted on your progress.
OMG .. i cant belive that u cross in my life at this bad time ..thanxs a lot for making it possible ..
Hopefully, things will turn around for you SOON!! Stay focused!!
Thanks again Dr. Neil for making this monster tame...... Silile
Thank you for this valuable source. Biostats is such a important part of the Steps and you make it so easy to comprehend!!
Thank You Dr.Neil !!! For making this so easy and lucid
OMG i love you. I had a hard time understanding HW equation until now.
you just made my life easier. a million thanks.
Thanks these are the best videos on Biostats, Please do more !
Best of the best on biostat, me as img was impossible , to learn w/o your videus . Thanks a lot doc
I don't think this matters to most people, but for the problem at 9:35, there's an easier way to calculate this vs doing all the negative flips and whatnot. Once you get to 0.02 = 29/x, just flip both equations so x is on the top and your life should get way easier. So:
X/29 = 1/0.02 --> multiply both sides by 29 to get X = 29/0.02 --> calculator time because the NBME is not entirely barbaric ==> 1450 is your answer
Great content. Dr. Neil will also share his notes upon request!
Amazing!!! Thank you so much. I now feel comfortable with biostats for the USMLE
You are the best lecturer I have ever seen 👌👌👏👏💐💐
You're timing couldn't have been better. Thank you...
I like to think that the difference between Length and Lead bias is in Length you were going to live LONG to begin with so it's benign cases; whereas Lead time you have a LEAD on a quick-killing disease.
Great videos Dr. Neil. Excellent Notes. Thank you so much for your hard work.
its the old wine , save it ,preserve it for the future ones!!! Huge thanks
Speedy, You are most welcome.
Guys this is not only good for Step 1!! I guarantee that you will come back for step 2CK and step 3!!!
Thank you Miguel for the kind comment.
thank you .,,,,
your technique helped me a lot....i had problem memorising all those stuff...now it will get more easy for me ahead
Beast mode Dr. Neil. Texas students would be much better off with you at the helm. Thank you.
Beast Mode...very nice.