Acorn Production
Suppose that the number of acorns that fall from a mature white oak tree in Bayfield County is strongly right-skewed with a mean of 875 and a standard deviation of 220.
- What is an individual?
- What is the variable?
- What are the appropriate symbols for the 875 and 220?
- Which distribution is strongly right-skewed?
I urge you to follow these steps when answering probability questions:
- Identify the distribution that would be used to answer the question (population or sampling).
- Identify characteristics of the required distribution; i.e., whether normal or not and, if normal, the center and dispersion (SD or SE).
- Identify whether the question can be answered or not (can be if normal, cannot be if not normal).
- Answer the question (see next box).
In all of the following questions, ...
- if the question can be answered then show a quick drawing that illustrates your calculation and the
distrib()
code used to compute the answer. - If the probability cannot be computed then explain why not (and be specific about which distribution is not normal).
- What is the probability that a sample of 50 oak trees will produce a mean of more than 900 acorns?
- What is the probability that a sample of 35 oak trees will produce a mean between 850 and 900 acorns?
- What is the probability that an oak tree produces more than 1000 acorns?
- What is the probability that a sample of 20 oak trees will produce a mean with fewer than 1000 acorns?
- What is the mean number of acorns for a sample of 35 oak trees that has a 15% probability of the mean being greater.