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1-20 of 318 Results
1. ### Nnt = 1 / arr

USMLE Step 1 Forum
New chemotherapy regimen is tested on 100 pts with lung cancer. 40 of pts are still alive after 1 yr. Conventional chemotherapy is given to separate group, 500 pts. with lung cancer and 100 are alive after 1 yr.. Calculate NNT. We know NNT = 1/ARR IN DIT THEY SAID THAT FORMULA FOR ARR IS [...
2. ### Two False Positive/Negative Questions

USMLE Step 1 Forum
1) A city with 1000 citizens has a 10% prevalence of disease x .. Screening shows sensitivity 80% and specificity 70% How many people without disease X will be falsely diagnosed positive by this screening test.. 1) 20 2) 30 3) 270 4) 300 2) A city with 1000 citizens has a 10% prevalence of...
3. ### Quick revision of Biostatistics

USMLE Step 2 CK Study Partners
I am planning to give exam in a month..so i need a dedicated sp to discuss important concepts of bio-stats and im quickly an hour everyday..i am from india so will prefer someone from same time zone..my skype id: vivek.dokan
4. ### Effect Modification versus Confounding Bias

USMLE Step 1 Forum
Can someone plz explain the difference between effect modification and confounding??
5. ### Odds Ratio; Im stuck!

USMLE Step 1 Forum
For patients with ambulance response intervals of longer than 5 minutes, more patients achieved Return Of Spontaneous Circulation in the CPR first group (58% [37/64]) compared with the standard De-fibrillation first group (38% [21/55]) Whats the OR? I can't figure out the steps to solve this...
6. ### Prevalence Odds Ratio

USMLE Step 1 Forum
In my FA I have for some completely forgotten reason scribbled down the words "prevalence odds ratio" and underlined it...and i cant remember wtf its from or what it is....I cant find anything on google, has anyone come across it?! or did i just completely make it up in a moment of study-psychosis?
7. ### Confounding and Effect Modification‏

USMLE Step 2 CK Forum
1- Confounding bias :(Middle factor that is related to both Exposure and Outcome) Alcohol ( exposure ) Oral cancer ( outcome ) Smoking is a confounding bias here. Because smoking is related to BOTH the exposure and the outcome. People who smoke will more often drink, and people who have...
8. ### A Complicated PPV Question!

USMLE Step 1 Forum
A test yields 80% infected and 10% non-infected.....prevalence is 10%. What is positive predictive value? A. 47% B. 54% C. 75% D. 25%
9. ### Bias Questions are Confusing

USMLE Step 1 Forum
Bias Questions in biostatistics are very confusing. Want to know how to improve my grip on this topic? any advice plz?
10. ### Effect Modification vs Confounding Bias

USMLE Step 1 Forum
I know that effect modification is not a bias...however they sound so similar...how do you guys differentiate between the two?
11. ### Small doubt in Epidemiology

USMLE Step 1 Forum
Guys right now I am doing Epidemiology from Kaplan and while I was watching kaplan videos and going through notes, I was stuck with these doubts. Please anyone take some time and answer 1) The definition of Sensitivity in Kaplan notes is as follows: "Sensitivity is the proportion of truly...
12. ### FA enough for Behavioral Sciences and Biostats

USMLE Step 1 Forum
can someone plz tell is FA & uworld enough for these two subjects?? plz rep..thanks in advance..God bless
13. ### how to improve in immunology and biostatic calculation ?

USMLE Step 1 Forum
can someone please advice me , how to improve the subject above , i did a stimulated test , and i scored badly for the above two subject , i have used kaplan , dit , but still ..... please advice , thanks .
14. ### Normal Distribution Question

USMLE Step 1 Forum
On a gross anatomy quiz, test scores of 10, 10, 10, 70, 40, 20, and 90 are obtained by seven students in a laboratory group. Which of the following correctly describes these quiz scores? (A) Positively skewed (B) A normal distribution (C) Negatively skewed (D) The mode is higher than the mean...
15. ### Positive Predictive Value Question

USMLE Step 1 Forum
A screening test is developed for assessing vulnerability to developing a certain condition. A sample of 10,000 people between the ages of 18 to 24 is recruited from the general population and given the screening test. Of this sample, 200 individuals are identified as likely to develop the...
16. ### Significant P Value but not much difference!

USMLE Step 1 Forum
Smokers among males = 35% in a population. Smokers among female = 34.1%. Chi square was done between the two groups and P<0.05 Is that possible? can be the difference between them significant although the percentage between the two populations is close?
17. ### Most important modifiable risk factor for Coronary Heart Disease

USMLE Step 3 Forum
what is the most important modified risk factor for CAD: DM HTN Smoking Central obesity Physical inactivity Thanks
18. ### Statistics question

USMLE Step 2 CK Forum
Study is made to analyze the relationship of vitamin B12 and methylmalonyl-COA level. Researchers show that there is an inverse relationship, the correlation coefficient is -0.7 (p<0.05). How much variability in plasma methylmalonyl-COA is explained by B12 intake? A) >0.95 B) 0.70 C) <0.05 D)...
19. ### Strange Biostats Concepts in NBME

USMLE Step 1 Forum
So I've done every single NBME from the offline and online forms. There are questions in the newer forms where it tests material that isn't in Kaplan or FA. Anybody know where I can go to fill these gaps in? For instance, they talk about "internal validity". Don't recall seeing this anywhere...
20. ### Biostats Prep for the CK Exam

USMLE Step 2 CK Forum
Guys..where to do the biostats for CK from? hardly anytime left :(
1-20 of 318 Results