Exhibit 7-12: an Investigator Is Studying the Effect of Two

Exhibit 7-12: An investigator is studying the effect of two physical fitness programs (M and N) on boys and girls.The experimental design is a 2 * 2 factorial design.The results of the investigation might be one of the following four conditions.
$\begin{array}{l}\begin{array}{lll}&\text { Condition (a) }\\&\mathrm{M} & \mathrm{N} \\\text { Boys }&\mathrm{X}=50 & \mathrm{X}=60 \\\text { Girls }&\mathrm{X}=60 & \mathrm{X}=50\end{array}\begin{array}{lll}&\text { Condition (b) }\\&\mathrm{M} & \mathrm{N} \\\text { Boys }&\mathrm{X}=50 & \mathrm{X}=60 \\\text { Girls }&\mathrm{X}=40 & \mathrm{X}=60\end{array}\end{array}$

$\begin{array}{l}\begin{array}{lll}&\text { Condition (c) }\\&\mathrm{M} & \mathrm{N} \\\text { Boys }&\mathrm{X}=50 & \mathrm{X}=40 \\\text { Girls }&\mathrm{Y}=60 & \mathrm{Y}=50\end{array}\begin{array}{lll}&\text { Condition (d) }\\&\mathrm{M} \quad\quad\quad\quad\quad\quad\quad\quad \mathrm{N} \\&\text { None of these condition }\\\\\end{array}\end{array}$

-Sampling error refers to

A) the mean difference between sample means.
B) the mean difference between population means.
C) the difference between a sample statistic and a population parameter.