What is the z-score of sample X, if #n = 169, mu= 41, St. Dev. =39, and E[X] =43#?

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Answer 1 · 2016-12-20T06:25:35

The answer is #=2/3#

The z-score for a sample mean is

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

#barx=E[X] =43#

#mu=41#

#sigma=39#

#n=169#

Therefore,

#z=(43-41)/(39/sqrt169)#

#=2/(39/13)#

#=2/3#