Question 1072204
at most 10 is z < (10-14)/2.1 or -1.905
probability z < -1.905 is 0.0284 or 2.84%
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z value for the 76th percentile is 0.705
0.705=(x-14)/2.1
1.4805-x-14
x=15.48 lb.
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That is 10% on each side which corresponds to a z value of +/-1.28
1.28=(x-14)/2.1
x-14=2.69
x=16.69 lb top end
x=11.31 pounds bottom end
(11.31 lb, 16.69 lb) is the interval.