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nbme24/Block 3/Question#10

Serum cholesterol concentrations are measured as ...


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submitted by m-ice(124),

This question only concerns women in the 50-54 age group. The group has a mean of 246 and standard deviation of 50. Therefore, all those with values greater than 296 are all those above one standard deviation. 2/3 of all values on a normal distribution are within one standard deviation in either direction. Therefore, 1/3 are outside of this in either direction, meaning 1/3 of women have a value less than 196 or greater than 296. If we split that in half to only choose those greater than 296, we get 1/6 women, which is about 16%.

guillo12  Sorry, but there is not other way that I can understand this? +1  
fulminant_life  @guillo12 basically 67% fall within 1 sd. That means that 33% are +/- >1sd. So taking only those with above 296, you only look at those >1sd above the mean which is 16.5% . The other 16.5% are those >1sd below the mean. +4  
guillo12  Thank you!!! @fulminant_life +  

look at FA 2019 pg. 261

in a Gaussian, 66% are within 1 SD and 95% within 2 SD

this is high yield af