In a particular large forest the percent of trees with a par

In a particular large forest, the percent of trees with a particular disease is 15%. In a random sample of 150 trees, there are 30 found with the disease. Is this an unusually large number of diseased trees? Explain.

Solution

in a sample of 150 we have

p = 30/150 =0.20

so this is an unusually large number of diseased trees because is greater than 0.15 that is the common percent of disease in a large forest