Question 1009884
A vending machine is designed to dispense a mean of 7.6 oz of coffee into an 8 oz cup. The standard deviation of the amount of coffee dispensed is .4 oz.
a. Find the percent the machine will dispense from 7.4 oz to 7.7 oz.
z(7.4) = (7.4-7.6)/0.4 = -0.5
z(7.7) = (7.7-7.6)/0.4 = 0.25
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P(7.4< x < 7.7) = P(-0.5< z < 0.25) = normalcdf(-0.5,0.25) = 0.2902
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b. Dispense less than 6.9 oz 
z(6.9) = (6.9-7.6)/0.4 = -1.75
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P(x < 6.9) = P(z < -1.75) = normalcdf(-100,-1.75) = 0.0401
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Cheers,
Stan H.