TABLE 16-2
the Monthly Advertising Expenditures of a Department

question 185

Essay

TABLE 16-2
The monthly advertising expenditures of a department store chain (in $1,000,000s) were collected over the last decade. The last 14 months of this time series follows:
$$\begin{array}{l}\begin{array} {cc } \text { Month}&\text { Expenditures } ( \$ )\\ \hline 1 & 1.4 \\2 & 1.8 \\3 & 1.6 \\4 & 1.5 \\5 & 1.8 \\6 & 1.7 \\7 & 1.9 \\8 & 2.2 \\9 & 1.9 \\10 & 1.9 \\11 & 2.1 \\12 & 2.4 \\13 & 2.8 \\14 & 3.1\end{array}\end{array}$$
-Referring to Table 16-2, set up a scatter diagram (i.e., time-series plot) with months on the horizontal X-axis.

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Definitions:

T-Test

A statistical test used to determine if there is a significant difference between the means of two groups.

Independent Populations

Populations that are not connected or influenced by each other, implying that the observations in one population are not affected by those in another.

Approximately Normal

Describes a distribution that closely follows a normal distribution, with slight deviations.

Normal Populations

Populations that exhibit a bell-shaped distribution curve, characterized by symmetry around the mean and decreasing frequency as the distance from the mean increases.