A few people in my class suggested calculating the z-scores and finding the probability using the normal distribution. However I didn't think this was possible given that we weren't given a standard distribution or anyway that I could perceive for calculating the mean.

Instead I had said that rolling a 6 was a 'success' with p=1/6 and rolling any other number was a 'failure' and that this was a binomial distribution, specifically the Poisson distribution since n is large and p is small. For lambda I had lambda = np =600(1/6) =100. Then i calculated Pr(90<X<100) = Pr(X=100) - Pr(X=90)

(using Pr(X=r) = lambda^r/r! (e^-lambda) for poisson I had) = 100^100/100! (e^-100) - 100^90/90! (e^-9). I calculated Pr(X=120) similiarly and said it was a very unlikely occurrence.

I have this question due soon and I'm feeling a bit lost. Any help at all would be greatly appreciated