A company that manufacturers Rivets believes the shear strength (in pounds ) is modeled by a normal distribution with a mean of 800 pounds, and a standard deviation of 50 pounds. 1. About what percent of rivets have a shear strength above 750 pounds? 2. About what percent of rivets have a shear strength between 700 and 900 pounds? 3. About what percent of rivets have a shear strength of more than 875 pounds? 4. About what percent of rivets have a shear strength over 675? 5. About what percent of rivets have a strength between 730 and 840? 6. About what percent of rivets have a shear strength under 865