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2 votes
in a population distribution a score of x=28 corresponds to z=-1.00 and a score of x=34 what is the mean and standard deviation

User Liz
by
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1 Answer

2 votes

x=28\implies z=\frac{28-\mu}\sigma\implies \mu-\sigma=28


x=34\implies z=\frac{34-\mu}\sigma\implies \mu+\sigma z=34

We need the exact value of
z to find a proper solution, but a general one can still be found. Subtracting the first equation from the second gives


(\mu+\sigma z)-(\mu-\sigma)=34-28\implies (z+1)\sigma=6\implies \sigma=\frac6{z+1}

Plug this into either equation and you get


\mu-\frac6{z+1}=28\implies \mu=28+\frac6{z+1}

(It's guaranteed that
z\\eq-1 in this case because that already corresponds to
x=28.)
User Sami Boussacsou
by
6.7k points
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