A Quality Analyst Wants to Construct a Sample Mean Chart

question 45

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: $$\begin{array} { l l c c l } \text { Day } && { \text { Weight (ounces) } } \\\hline \text { Monday } & 23 & 22 & 23 & 24 \\\text { Tuesday } & 23 & 21 & 19 & 21 \\\text { Wednesday } & 20 & 19 & 20 & 21 \\\text { Thursday } & 18 & 19 & 20 & 19 \\\text { Friday } & 18 & 20 & 22 & 20\end{array}$$
What is the mean of the sampling distribution of sample means when this process is in control?

• A) 18 ounces
• B) 19 ounces
• C) 20 ounces
• D) 21 ounces
• E) 22 ounces

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Definitions:

Tri-modal Profile

A statistical distribution in which three modes or peaks are present, indicating three dominant values or traits in the data set.

Z Distribution

A normalization of the standard normal distribution, which is symmetric about the mean, showing the relationship between data points and their standard deviations.

Normal Curve

A bell-shaped curve that represents the distribution of values, with most occurring around a central region.

T Test

A statistical test for assessing whether the mean scores for two groups are significantly different.