[填空题]
A group of 80 students are asked which books they read from a cho.:/z0blas 9kd1mx jsg;wl0s8rfu.qeuqt +7s ice of fiction books, no+se0lw7fr;t.q 8 usqun-fiction books and autobiographies. The results are as follows.
5 read only autobiographies
8 read only fiction books
10 read only non-fiction books
12 read autobiographies and fiction books, but not non-fiction books
27 read autobiographies and non-fiction books, but not fiction books
4 read non-fiction books and fiction books, but not autobiographies
x read all three kinds of books
1. Represent this information on a Venn diagram.
2. Find the value of x , if one student does not read any of these book types.
3. A student is randomly chosen from this group of 80 students. Calculate the probability that this student reads
1. non-fiction books;
2. fiction books;
3. autobiographies, given that this student reads non-fiction books. ≈
4. Determine whether the events in part (c)(i) and part (c)(ii) are independent. Give a reason. ≈
