Question

out of the people who have already taken their seats at a seminar, 2 people have black hair while 2 people do not. considering this data, how many of the next 16 people to take their seats should you expect to be black - haired? black - haired people

Explanation:

Step1: Calculate the proportion of black - haired people

The total number of people already seated is $2 + 2=4$. The number of black - haired people among them is 2. So the proportion of black - haired people is $\frac{2}{4}=\frac{1}{2}$.

Step2: Predict the number of black - haired people in the next group

We have 16 new people. Multiply the proportion of black - haired people by the number of new people. So the expected number of black - haired people is $\frac{1}{2}\times16 = 8$.

Answer:

8