Question

1. In the African savannah, elephants like to eat very young trees. Imagine that, in a section f the savannah, the mean height of young trees is 20.0 cm with a variance of 16.0 cm². Assume that young tree height is normally distributed.
   1. (4 pts) What percentage of young trees would be eaten if elephants eat all trees shorter than 26.0 cm?
   2. (4 pts) In a section of the savannah, there are many young trees. If we take a random sample of 90 trees what is the probability that the mean height of our sample is 30.0 cm?
   3. (2 pts) BRIEFLY compare and contrast the Z distribution and the t-distribution. For instance if you used the t-distribution instead of the Z distribution for the above question, how would your critical values have differed? You might consider a relevant drawing, if that would be helpful in your answer.

Answer 1