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#1
07-15-2012
 USMLE Forums Master Steps History: 1+CK+CS Posts: 1,867 Threads: 149 Thanked 2,085 Times in 1,046 Posts Reputation: 2105
100 versus 1000 Samples; Standard Deviations!

Investigator A takes a random sample of 100 men age 18-24 in a community. Investigator B takes a random sample of 1,000 such men.

a. Which investigator will tend to get a bigger standard deviation (SD) for the heights of the men in his sample? Or, can it not be determined?

b. Which investigator will tend to get a bigger standard error of the mean height? Or, can it not be determined?

c. Which investigator is likely to get the tallest man? Or are the chances about the same for both investigators?

d. Which investigator is likely to get the shortest man? Or are the chances about the same for both investigators?

#2
07-15-2012
 USMLE Forums Master Steps History: 1+CK+CS Posts: 646 Threads: 52 Thanked 760 Times in 256 Posts Reputation: 771

the standard deviation will decrease

standard error of the mean will also decrease as the number of subjects increases.

c. Which investigator is likely to get the tallest man? Or are the chances about the same for both investigators?
d. Which investigator is likely to get the shortest man? Or are the chances about the same for both investigators?

but i think the 1st one with the lesser sample size has more chances of having outliers on both sides

 Tags Biostatistics-Epidemiology, Step-2-Questions

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