:1. Solution. : SE sum of draws = 25x5 =125 SE average of draws = 125/25 = 5

: SE average of draws = 5

SE of difference of averages = (5^2 + 5^2)^(1/2) = (50)^(1/2) = 7.07

z = ((reg. ex. av. - no reg. ex. av.) - 0)/ SE difference of ave's

= (132 -121)/7.07 = 11/7.07 = 1.55

The area under the normal curve between -1.55 anmd 1.55 is 87.89%. Since 100 - 87.89 = 12.1%, and since 12.1/2 = 6.05%, the closest of the choices is 5%. ! !I