The Haunted House, by R. A. Montgomery. New York: Bantam/Skylark. 56 pp.

In a delightful new Bantam series, for the 7- to 9-year-old, the reader is the central character. Every page or so, he or she faces a choice about how the action will proceed.

In ''The Haunted House'' the text explains: ''You and your dog Homer are walking home from school for lunch one day.'' Homer chases a cat into a scary-looking old house, and, ''If you go into the house, turn to page 9.'' Or ''If you run away, turn to page 5.'' Decisions! Decisions!

Depending on the reader's choices, there are more than a dozen possible endings. Children can reread the book again and again with a different adventure each time.

Enthusiastic teachers and school librarians say the adventures, ranked sixth among the most popular children's books of the last two years in a Publisher's Weekly survey, teach children to make decisions and help get slower readers interested in books.