You could restate it as "what is the probability that <30 say they agree with the new spped limit?".Originally Posted byrebeccajm

.075(400)=30

Use

Don't forget the continuity correction for x. In a binomial distribution, the possible midpoint values for "fewer than 30" are ....27, 28, 29.

Add 0.5 to the right hand boundary to get x=29.5.

Look up the z-score in the table.