Instruction 12 -Referring to Instruction 12 $S _ { b _ { 1 } }$

Instruction 12.27
The director of cooperative education at a university wants to examine the effect of cooperative education job experience on marketability in the workplace. She takes a random sample of four students. For these four, she finds out how many times each had a cooperative education job and how many job offers they received upon graduation. These data are presented in the table below.
$$\begin{array} { | l | l | l | } \hline \text { Student } & \text { Coop jobs } & \text { job Offer } \\\hline 1 & 1 & 4 \\\hline 2 & 2 & 6 \\\hline 3 & 1 & 3 \\\hline 4 & 0 & 1 \\\hline\end{array}$$
-Referring to Instruction 12.27,the director of cooperative education wanted to test the hypothesis that the true slope was equal to 0.The denominator of the test statistic is $S _ { b _ { 1 } }$ .The value of $S _ { b _ { 1 } }$ in this sample is____________