Table 1:

An academic awareness task force at a Big-Ten university sampled 200 students to ask them whether they studied or did not study the weekend before the midterm. The following result was obtained:

The probability tree is shown in FIGURE 1.

Referring to Table and Figure 1, the P(W | S) is:

Studied for Exam (s) Did not study for Exam (s') Total Did Well on Midterm (W) 80 30 110 Did Poorly on Midterm (W') 20 70 90 Total 100 100 200 Tree diagram: P(S) = 0.5 P(S)=0.5 Figure 1 P(w/s)=0.50 P(w/s)=0.50 P(w/s')=0.5524 P(w/s') = 0.5524