Question #d87c1

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Answer 1 · 2016-02-20T19:16:14

If 25% lies in the middle of the distribution, 75% must lie outside it.

Also, #(75%)/2=37.5%# lies to the left of -z or more simply, #37.5%+25%=62.5% lies to the left of z ...

Now use a Standard Normal Table to look up z:

#P(Zltz)=0.625#

#z=0.319#

And, because the Standard Normal is perfectly symmetric ...

#-z=-0.319#

Now, check the answer ...

#P(-0.319< z < 0.319)= 0.25#

hope that helped