Question 1:

In a study of incomes of individual adults in the United States, it is observed that many people have no income or very small incomes, while there are very few people with extremely large incomes, so a graph of the incomes is skewed instead of being symmetric. A researcher states that because incomes are a normal occurrence, the distribution of incomes is a normal distribution. Is that statement correct? Why or why not?

Question 2:

Why are manhole covers usually round?