<PRE><B>Question 1066528</B>
z=(x-mean)/sd
mean is 169 and sd is 6
x is the value given
z=(151-169)/6 and that is -18/6 or -3
z=(187-169)/6=18/6=3
so you want z to be between -3 and 3. That is by the empirical rule 99.7%
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For 157 and 181
z=(157-169)/6=-2, because -12/6=-2
z=(181-169)/6=2
That is z between -2 and 2, which by the empirical rule is 95%</PRE>