TABLE 15-7
a Chemist Employed by a Pharmaceutical Firm Has

TABLE 15-7
A chemist employed by a pharmaceutical firm has developed a muscle relaxant. She took a sample of 14 people suffering from extreme muscle constriction. She gave each a vial containing a dose (X) of the drug and recorded the time to relief (Y) measured in seconds for each. She fit a "centered" curvilinear model to this data. The results obtained by Microsoft Excel follow, where the dose (X) given has been "centered."
SUMMARY OUTPUT
$$\begin{array}{l}\begin{array} { l r } \begin{array} { l } \end{array} \\\hline\text { Regression Statistics }\\\hline \text { Multiple R } & 0.747 \\\text { RSquare } & 0.558 \\\text { Adjusted R Square } & 0.478 \\\text { Standard Error } & 863.1 \\\text { Observations } & 14 \\\hline\\\end{array}\\\text { ANOVA }\\\begin{array} { l r r r l l } \hline & d f &{ \text { SS } } & \text { MS } & F & \text { Significance } F \\\hline \text { Regression } & 2 & 10344797 & 5172399 & 6.94 & 0.0110 \\\text { Residual } & 11 & 8193929 & 744903 & & \\\text { Total } & 13 & 18538726 & & & \\\hline\end{array}\\\\\begin{array} { l c c c c } \hline & \text { Coeff } & \text { Std Error } & t \text { Stut } & p \text {-value } \\\hline \text { Intercept } & 1283.0 & 352.0 & 3.65 & 0.0040 \\\text { CenDose } & 25.228 & 8.631 & 2.92 & 0.0140 \\\text { CenDoseSq } & 0.8604 & 0.3722 & 2.31 & 0.0410 \\\hline\end{array}\end{array}$$
-Referring to Table 15-7, suppose the chemist decides to use a t test to determine if there is a significant difference between a curvilinear model without a linear term and a curvilinear model that includes a linear term. Using a level of significance of 0.05, she would decide that the curvilinear model should include a linear term.