Dismiss Notice
Hey Texans—join us for a DFW meetup! Click here to learn more.

Please help the statistically challenged

Discussion in 'Step I' started by souljah1, Apr 3, 2004.

  1. souljah1

    souljah1 Attending
    10+ Year Member

    Joined:
    Feb 7, 2002
    Messages:
    1,667
    Likes Received:
    6
    Someone please help me out with this. I am terrible at statistics.

    Could someone please show me how to compare scores from the NBME and the USMLE.

    Example: Johnny gets a 570 on the NBME self assessment. He is relieved to find out that he has scored above the mean, but when he asks himself what his score would equate to on the real thing he becomes irritated and confused. The mean on the self assessment is 500 with a standard deviation of 100. If the mean of USMLE step1 is 216 with a standard deviation of 24, what score on step1 is equivalent to a 570 on the NBME?

    I've heard z-scores are involved so I figured I'd consult the experts...

    For full credit you must show your work.
     
  2. Note: SDN Members do not see this ad.

  3. ice_23

    ice_23 Economics Monster
    7+ Year Member

    Joined:
    Jul 21, 2003
    Messages:
    1,208
    Likes Received:
    1
    The equivalent score of a 570 (given your numbers) is a 232-233 on the USMLE.

    -Ice
     
  4. Of course, let's not all place TOO much emphasis on the NMBE practice tests. Everyone wants to know, "if I score x % in QBank, or y % on the NMBE exam, or z % in BSS, what will I get on the real thing?" Obviously there's no way to predict how you'll do. The very fact that the actual test is 8 hours long kinda diminishes the value of the (shorter) practice tests.
     
  5. Al Pacino

    Al Pacino Senior Member
    7+ Year Member

    Joined:
    Aug 15, 2002
    Messages:
    123
    Likes Received:
    1
    ok, here goes. Johnny scores 570. His score was mean(500)+ 70% of standard deviation (SD=100) or 500 + 0.7 x 100 or 570.

    Ok, let's apply this correlation to the boards. Johnny's projected board score would be mean + 0.7 x SD or 216 + 0.7 x 24= 216+ 16= 232.
     
  6. Jalby

    Jalby I fight crime at day when Batman are sleeping.
    10+ Year Member

    Joined:
    Aug 24, 2001
    Messages:
    5,521
    Likes Received:
    1,572
    Status:
    Pre-Veterinary
    I thought the Standard dev for the boards was about 16?? Am I mistaken??
     
  7. On the one that I took (last June), mean was 217, standard deviation was 24. The standard deviation was smaller a few years ago.
     

Share This Page