# Proportion basic question

#### mazatlan

##### New Member
Note: This is not homework, I am a Biologist trying to learn basic statistics.
Hi, I am trying to learn basic probability and I would like to get the answer of the questions below. I honestly have not idea on how to even start solving it. Could someone show me or give me some advice on how to tackle it? Much appreciated...

Wild lizards are found in a particular mountain range in Australia at an abundance of 1.4 per 6 square miles. The standard deviation of lizard abundance is 0.4 per 5 squares miles. Assume that lizard abundance is a random variable that has a bell-shaped distribution.

a. If you pick a random 12 square mile area in this mountain range, what is the likelihood that there are more than 7 lizards in this area?

b. If you pick a random 5 square mile area in this mountain range, what is the likelihood that there are between 1 and 3 lizards in this particular 5 square mile area?

#### EdGr

##### Member
This looks like a z score problem that assumes you know how to get the SD of a sum of random variables. But one critical question to you -- are you SURE the stem uses 6 square miles for the mean and 5 square miles for the SD? And that part B uses 5 square miles (not 6)? Part B would be a very straightforward z-score calculation if it was 6 square miles and the SD and mean were for 6. The mismatch makes this something other than "basic statistics" in my opinion!

#### mazatlan

##### New Member
I reviewed my question and you are correct, and it should be 6 square miles and 6 square miles for the SD. However, I read a few proportion tutorials and was able to figure it out on my own. Thanks for looking into it.