median calculation - USMLE Forums
 USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
 Home USMLE Articles USMLE News USMLE Polls USMLE Books USMLE Apps
 USMLE Forums median calculation
 Register FAQs Members List Search Today's Posts Mark Forums Read

 USMLE Step 2 CK Forum USMLE Step 2 CK Discussion Forum: Let's talk about anything related to USMLE Step 2 CK exam

#1
04-11-2014
 USMLE Forums Addict Steps History: 1+CK+CS Posts: 171 Threads: 67 Thanked 20 Times in 18 Posts Reputation: 30
median calculation

may be this is silly for alot of you , but if there is repeated readings how we calculate the median , do we use it once or more ??as i know from step 1 we use it once but here in uworld it is different
if you have (18,20,21,22,22) what is the median ??? and why ?

#2
04-11-2014
 USMLE Forums Veteran Steps History: 1+CK+CS Posts: 259 Threads: 8 Thanked 115 Times in 78 Posts Reputation: 125

Quote:
 Originally Posted by hydrocephalus may be this is silly for alot of you , but if there is repeated readings how we calculate the median , do we use it once or more ??as i know from step 1 we use it once but here in uworld it is different if you have (18,20,21,22,22) what is the median ??? and why ?
Median is the MIDDLE number. You have 5 numbers total. Spiting the numbers in half. 18, 20 on one side and 22, 22 on the other side. the middle is 21.

Mode is the most common reoccurring number. so that would be 22.

Mean is average. 103/5 = 20.6
__________________
2015 grad , Step 1-[X], Step 2CK [X], Step 2 CS [X] , Step 3 [X], MATCHED IM 2015. PGY-1 to Infinity.
 The above post was thanked by: hydrocephalus (04-12-2014)
#3
04-11-2014
 USMLE Forums Veteran Steps History: 1+CK+CS Posts: 259 Threads: 8 Thanked 115 Times in 78 Posts Reputation: 125

Also.

Dr. wikipedia provides a good explanation.

In statistics and probability theory, the median is the numerical value separating the higher half of a data sample, a population, or a probability distribution, from the lower half. The median of a finite list of numbers can be found by arranging all the observations from lowest value to highest value and picking the middle one (e.g., the median of {3, 3, 5, 9, 11} is 5). If there is an even number of observations, then there is no single middle value; the median is then usually defined to be the mean of the two middle values [1] [2] (the median of {3, 5, 7, 9} is (5 + 7) / 2 = 6), which corresponds to interpreting the median as the fully trimmed mid-range. The median is of central importance in robust statistics, as it is the most resistant statistic, having a breakdown point of 50%: so long as no more than half the data is contaminated, the median will not give an arbitrarily large result. A median is only defined on ordered one-dimensional data, and is independent of any distance metric. A geometric median, on the other hand, is defined in any number of dimensions.
__________________
2015 grad , Step 1-[X], Step 2CK [X], Step 2 CS [X] , Step 3 [X], MATCHED IM 2015. PGY-1 to Infinity.
 The above post was thanked by: hydrocephalus (04-12-2014)
#4
04-12-2014
 USMLE Forums Addict Steps History: 1+CK+CS Posts: 171 Threads: 67 Thanked 20 Times in 18 Posts Reputation: 30

Quote:
 Originally Posted by mdsoon Also. Dr. wikipedia provides a good explanation. In statistics and probability theory, the median is the numerical value separating the higher half of a data sample, a population, or a probability distribution, from the lower half. The median of a finite list of numbers can be found by arranging all the observations from lowest value to highest value and picking the middle one (e.g., the median of {3, 3, 5, 9, 11} is 5). If there is an even number of observations, then there is no single middle value; the median is then usually defined to be the mean of the two middle values [1] [2] (the median of {3, 5, 7, 9} is (5 + 7) / 2 = 6), which corresponds to interpreting the median as the fully trimmed mid-range. The median is of central importance in robust statistics, as it is the most resistant statistic, having a breakdown point of 50%: so long as no more than half the data is contaminated, the median will not give an arbitrarily large result. A median is only defined on ordered one-dimensional data, and is independent of any distance metric. A geometric median, on the other hand, is defined in any number of dimensions.

thank you so much , i had this doubt about repeated values if we use it or not
#5
04-12-2014
 USMLE Forums Veteran Steps History: 1+CK+CS Posts: 259 Threads: 8 Thanked 115 Times in 78 Posts Reputation: 125

Quote:
 Originally Posted by hydrocephalus thank you so much , i had this doubt about repeated values if we use it or not
a repeated value is just another data point. think of it as 5 different people who provide 5 different scores for the same single test.
__________________
2015 grad , Step 1-[X], Step 2CK [X], Step 2 CS [X] , Step 3 [X], MATCHED IM 2015. PGY-1 to Infinity.
#6
04-19-2014
 USMLE Forums Scout Steps History: Step 1 Only Posts: 18 Threads: 4 Thanked 11 Times in 8 Posts Reputation: 21

Quote:
 Originally Posted by hydrocephalus may be this is silly for alot of you , but if there is repeated readings how we calculate the median , do we use it once or more ??as i know from step 1 we use it once but here in uworld it is different if you have (18,20,21,22,22) what is the median ??? and why ?
More difficult will be if there was 18, 20, 22, 22

In that case median will be middle two divided by two 20+22=42 /2 = 21 .

Message:
Options

## Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
User Name:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
 AMG IMG ---
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

 Not yet Step 1 Only CK Only CS Only 1 + CK 1 + CS 1+CK+CS CK+CS 1+CK+CS+3 ---
Favorite USMLE Books
 What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
 Where you live. Leave blank if you don't want to tell.

## Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.