The mid-point of a class is called its Class Mark.

If the class marks of a distribution are $28, 34, 40, 46, 52$; then the class intervals are of length _____.

If the class marks in a frequency distribution are $19.5, 26.5, 33.5, 40.5, 47.5, 54.5, 61.5$; then the class size of the distribution is _____.

The class mark of the class interval $10-19$ is _____.

The class mark of the class interval $9.5-16.5$ is _____.

State whether "Size of shoes" is Discrete Data / Continuous Data.

State whether the following variable is continuous or discrete:

Number of pages in a book.