A Researcher Wanted to See the Effects of Different Learning $\quad$

A researcher wanted to see the effects of different learning strategies. A control group simply read the book Discovering Statistics (Book) , a second group read the book and completed the 'end of chapter exercises' (Book & Exercises) , and a third group read the book, did the end of chapter exercises and also completed the web materials (All Activities) . The researcher predicted that the 'all activities' and 'book and exercises' groups would perform better than the book group on a subsequent test, but that the 'book and exercises' group would perform worse than the 'all activities' group. Which coding scheme would test these hypotheses in a set of planned comparisons? (Hint: The sum of weights for a comparison should be zero. If you add up the weights for a given contrast the result should be zero.)

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D) $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$ Case Summaries ${ }^{a}$
$\begin{array}{|l|l|r|r|r|}\hline &{\text { Contrast }} & {\text { Book }} & \begin{array}{c}\text { Book \& } \\\text { Exercises }\end{array} & \text { All Activities } \\\hline 1 & \text { Contrast 1 } & 2 & -1 & -1 \\2 & \text { Contrast 2 } & 0 & -1 & -1 \\\hline\end{array}$

a. Limited to first 100 cases.