(i)[1]
Estimate the probability of rolling a $4$.
(ii)[1]
Hence find the variance for the number of $4$s obtained in $30$ throws.
(iii)[3]
Find the probability that in $15$ throws the count of $4$s obtained is $2$ or more.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
A biased die is thrown $30$ times, and the number of $4$s is recorded. The experiment was carried out repeatedly, and the mean count of $4$s in $30$ throws came out as $6.21$.