A Quality Analyst Wants to Construct a Sample Mean Chart

question 25

Multiple Choice

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each: $$\begin{array} { l l c c c } \text { Day } && { \text { Weight (ounces) } } \\\hline \text { Monday } & 23 & 22 & 23 & 24 \\\text { Tuesday } & 23 & 21 & 19 & 21 \\\text { Wednesday } & 20 & 19 & 20 & 21 \\\text { Thursday } & 18 & 19 & 20 & 19 \\\text { Friday } & 18 & 20 & 22 & 20\end{array}$$
What is the standard deviation of the sampling distribution of sample means for whenever this process is in control?

• A) 0.1 ounces
• B) 0.4 ounces
• C) 0.5 ounces
• D) 1 ounce
• E) 2 ounces

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Definitions:

Standard Deviation

An indicator of how much the values in a dataset spread out or vary from one another.

Standard Error

A measure of the statistical accuracy of an estimate, indicating the variability of sample means around the population mean.

Mean

A statistical measure representing the central or typical value in a set of data, calculated as the sum divided by the number of observations.

Directional

Pertains to hypotheses or tests that specify the expected direction of the relationship or difference between variables, as opposed to non-directional or two-tailed tests.