To find the standard deviation is a binomial distribution, you have to take the square root of the total number multiplied by the percent and its compliment.
The only reason it will be 200 is because the numbers 1,2,3,4,5,and 6 are all an option so the probability of 5 is 1/6 and if you multiply 1/6 by 1,200 you will get 200. Hope this helped!
