A wildlife biologist examines frogs for a genetic trait he suspects may be linked to sensitivity to industrial toxins in the environment. Previous research had established that this trait is usually found in 1 of every 8 frogs. He collected and examines a dozen frogs. If the frequency of the traits has not changed, what\'s the probability he finds the trait in no more than 4 frogs? Solution P = 1/8 P( 0 frog ) + P( 1 frog ) + P( 2 frog ) + P( 3 frog ) + P( 4 frog ) =( 7/8 )^12 + 12 * ( 1/8 ) * ( 7/8 )^11 + 66 * ( 1/8 )^2 * ( 7/8 )^10 + 220 *( 1/8 )^3 * ( 7/8 )^9 + 495 *( 1/8 )^4 * ( 7/8 )^8 =0.9887145218963269 = 0.9887 = 98.87%.