Sounds like you should use a test here.
Observed sex ratio can be described by the Expected sex ratio
Observed sex ratio differs from the Expected sex ratio
Now you need to make a table
Populate this table and find
A biologist discovers a colony of a previously unknown type of bird nesting in a cave. Out of the 16 chicks which hatch during his period of investigation, 13 are female. Test at the 5% significance level whether this supports the view that that the sex ratio for the chicks differs from 1.
Im really stuck i think ive developed the p:H1 and p:H0 but after that i am a bit stuck any help is much appreciated thankyou