Aman is 6 feet 2 inches tall. to find the height of a tree, the shadow of the man and the shadow of the tree were measured. the length of the man's shadow was 2 feet 1 inch. the length of the tree's shadow was 3 feet 7 inches. what is the height of the tree?

12.9 ft
10.6 ft
14.3 ft
10.9 ft

6ft2inch/2ft1inch=a/3ft7inch

a would be something like 10.9ft

She asked her friends, which does not represent a random sample.

She tried to show cause and effect without doing an experiment (which includes simple random sample, control group, treatment, etc).

So the answer is she did not use a random sample, and tried to show cause and effect with an observational study.