Question 322735
It appears you are working a problem associated
with Chebyshev's Theorem.  If that is true the
following procedure applies:
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 please help! Bags of Flour • The weights of bags of flour are normally distributed, with a mean of 5 pounds (80 ounces) and a standard deviation of 0.5 ounce. Determine an interval of values into which 

(a) about 95% of the bags of flour will fall and 
According to Chebyshev, 95% of the data lies within 2 standard 
deviations of the mean.  For your problem that would be 
80-2(0.5) oz up to 80+2(0.5) oz
79 oz to 81 oz
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(b) about 68% of the bags of flour will fall.
According to Chebyshev, 68% of the data lies within 1 standard
deviation of the mean. For your problem that would be 
80-0.5 up to 80+0.5
79.5 oz up to 80.5 oz
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Cheers,
Stan H.