A Quality Analyst Wants to Construct a Sample Mean Chart

question 45

Essay

A quality analyst wants to construct a sample mean chart for controlling a packaging process.He knows from past experience that the process standard deviation is two ounces.Each day last week,he randomly selected four packages and weighed each.The data from that activity appears below. (a)Calculate all sample means and the mean of all sample means.
(b)Calculate upper and lower control limits that allow for natural variations.
(c)Is this process in control?

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Definitions:

Standard Deviation

A statistic that measures the dispersion of a dataset relative to its mean and is calculated as the square root of the variance.

Stock A

A generic term used to represent a share in the ownership of a company, typically entitling the shareholder to a portion of the profits.

Mean-Variance Efficient Portfolio

A portfolio constructed to have the highest possible expected return for a given level of risk.

Covariances

A measure of how two variables move in relation to each other, indicating the degree to which they vary together.