Assume trees in a plantation have heights 42 metres with standard deviation of 15 metres. the plantation is considered ready for logging if a sample of these trees has a mean height exceeding 37 metres.

A) if 45 trees were sampled, what is the chance that the plantation is considered ready for logging based on the mean height of this sample

B) how many trees should have been sampled in order for the chance of not logging to be only 9%