Through extensive study, we know that the wingspans of the Purple-Throated Hummingbird are normally distributed with a mean of 14.1cm and a standard deviation of 1.7cm. They are endangered, so in 2020, we measured every single one to form our dataset.

1. What is the unit of observation in this case? Is the data a census or a sample?
2. Draw a quick sketch/diagram showing the distribution, mean and standard deviation of the population
3. My pet hummingbird has a wingspan of 10.7cm. Using the 68 - 95 - 99.7%. rule or any other method, what percentage of current Blue-Throated Hummingbirds have a wingspan greater than this?
4. In your diagram in 3b. shade ~ the top 10%. Given that and the 68 - 95 - 99.7 rule, tell me your rough guess for what wingspan is greater than 90% of the population.
5. Now calculate it formally using a Z score. E.g. given our assumptions above, what wingspan is greater than 90% of the population? Happy with your answer from d?