② The data is: 0.35× 100=35.

(2) There are 20+20+ 10=50 students in group 345.

Therefore, the sampling ratio k= 5 50 = 1 10.

So the fourth group should choose 20× 1 10 =2 people.

We should choose10×110 =1from the fifth group.

(3) Record "at least one student in Group 4 was selected" as event A.

There are C 25 = 10 different situations from "randomly selecting two students for interview" * *;

At least one student was drawn in the fourth group, including C 12? C 13+C 22 =7 different situations;

So P(A)= 7 10 =0.7.