/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 90 At Jen and Perry Ice Cream Compa... [FREE SOLUTION] | 91Ó°ÊÓ

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At Jen and Perry Ice Cream Company, a machine fills 1-pound cartons of Top Flavor ice cream. The machine can be set to dispense, on average, any amount of ice cream into these cartons. However, the machine does not put exactly the same amount of ice cream into each carton; it varies from carton to carton. It is known that the amount of ice cream put into each such carton has a normal distribution with a standard deviation of 18 ounce. The quality control inspector wants to set the machine such that at least \(90 \%\) of the cartons have more than 16 ounces of ice cream. What should be the mean amount of ice cream put into these cartons by this machine?

Short Answer

Expert verified
The machine should be set to fill the cartons with a mean amount of approximately 2.44 pounds of ice cream.

Step by step solution

01

Calculate the Z-score for 90 % of the Distribution

Since the quality control inspector wants at least 90% of the cartons to have more than 16 ounces of ice cream, this infers the remaining 10% may have less. Consequently, using a Z-table or a calculator which provides the same statistical functionality, you need to find the Z-score for 90%. To be more specific, look for the Z-score, which corresponds to the probability of 0.1 (10 % remaining) being below this Z-score. This yields a Z-score of approximately -1.28.
02

Use Z-score formula to Find the Mean

The standard Z-score formula is \(Z = (X - \mu) / \sigma\), where \(\mu\) is the mean, \(\sigma\) is the standard deviation, and \(X\) is the observed value. In the given problem, \(\sigma = 18\) ounces (converted to pounds), \(X = 16\) ounces (converted to pounds), and \(Z = -1.28\) (from previous step). Solving the Z-score equation for \(\mu\) gives us the formula \(\mu = X - Z \cdot \sigma\). Plug in the known values and solve for the mean.
03

Solve for the Mean

By substituting the values into the equation we get: \(\mu = 1 - (-1.28 * 1.125)\). This gives us a mean of approximately 2.44 pounds.

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