President Obama proposed the elimination of taxes on dividends paid to shareholders on the grounds that they result in double taxation. The earnings used to pay dividends are already taxed to the corporation. A survey by Dr Greg on this issue revealed that 47% of Americans favor the proposal. By political party, 64% of the democrats and 29% of the Republicans favor the proposal. Suppose a group of 250 Americans gather to hear a speech about the proposal.
What is the probability that at least half of the group is in favor of the proposal?
I tried solving it Using normal approximation to binomial but I'm not sure
The survey is a Bernouilli trial (yes/no, heads/tails, in favour of/against) so the binomial distribution applies.
The mean is np=250*0.47=117.5 and the standard deviation is s=sqrt(npq)=7.9.
I can't continue from here