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Old 11-03-2012
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Default Biostat

Serum LDL conc are measured in blood sample collected from 100 healthy volunteers. The data follow normal distribution. The mean and standard deviation for this group is 130 mg/dl and 20mg/dl. Standard error of mean is 5.0. 95 % confidence interval about mean is 120 - 140 mg/dl. If blood samples are collected from 25 volunteers instead of 100, which of the following best expressed the expected impact on standard error and 95% confidence interval about the mean ?
Standard error Width of 95% CI
A. de de
B. de in
C de no change
D in de
E in in
F in no change
G no change de
H no change in
I no change no change
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  #2  
Old 11-03-2012
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i think it's E..........increase increase

if sample size decrease------standard error increase which eventually increase 95% CI .

thanks
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  #3  
Old 11-03-2012
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Default my answer :)

E in in
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