Question 1019416
z=(x-mean)/sd
between 110 and 145 is a z between -30/10 (-3) and a z of (5/10) or 1/2
That probability is 0.6901. and that is 138 students.
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Fewer than 120 pounds is fewer than -2 sd.  The probability is 0.02275, and that is 5 students, rounded.
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more than 170 pounds is more than +3 sd.  The probability is 0.00134, and that would be 0 students, rounded (Expected value is 0.27)