To send a letter by mail Letters have damaged 15% of the sample of 310 people, random letters to random people who just two original shows that 260 people received a letter two copies in good condition, 40 people have received the first version was damaged first edition and. there are 10 people who have been damaged in the mail two copies of the letter that the test be damaged. Explained the partnership binomial or not. The more important 0.10 level.