題組內容

4. (15%) Given below are five observations collected in a regression study on two variables, x (independent variable) and y (dependent variable).

\( \bar{x} = 4 \), \( \bar{y} = 2.8 \), \( S_{xx} = 10 \), \( S_{yy} = 6.8 \), \( S_{xy} = -8 \)

b. At \( 95\% \) confidence, perform a \( t \) test and determine whether or not the slope is significantly different from zero.