What is the z-score of sample X, if #n = 121, mu= 55, St. Dev. =110, and E[X] =107#?

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Answer 1 · 2016-11-24T07:04:27

The z-score is #=5.2#

The z-score for a sample mean is given by

#z=(barx-mu)/(sigma/sqrtn)#

where

#barx=[X]=107#

#mu=55#

#sigma=110#

#n=121#

#z=(107-55)/(110/sqrt121)=52/(110/11)=52/10=5.2#