Show the following data by a frequency polygon.

Time alloted for the preparation of an examination by some students is shown in the table. Draw a histogram to show the information.

Observe the following frequency polygon and write the answers of the questions below it.

(1) Which class has the maximum number of students?

(2) Write the classes having zero frequency.

(3) What is the class-mark of the class, having frequency of 50 students?

(4) Write the lower and upper class limits of the class whose class mark is 85.

(5) How many students are in the class 80-90?

The following table shows the classification of percentages of marks of students and the number of students. Draw a frequency polygon from the table.

The age group and number of persons, who donated blood in a blood donation camp is given below. Draw a pie diagram from it.