(i)[3]
Find the standard deviation of the lengths of these videos.
(ii)[4]
Find the probability that a randomly chosen video has a length that is less than half a minute away from the mean.
(iii)[2]
Without doing any further calculation, determine whether $p$ is more than, equal to, or less than your answer in part (ii). You must give a reason for your decision.
(c(iii))[2]
Without doing any further calculation, decide whether $p$ is more than, equal to, or less than your answer to part (ii). You must explain how you reached your conclusion.