What is the z-score of sample X, if #n = 196, mu= 45, St. Dev. =28, and E[X] =29#?

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Answer 1 · 2016-12-29T14:38:00

The answer is #=-8#

The z-score for a sample mean is

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

#barx=E[X] = 29#

#mu=45#

#sigma=28#

#n=196#

Therefore,

#z=(29-45)/(28/sqrt196)#

#=-16/(28/14)#

#=-16/2=-8#