Find the class-mark of the class 35-40.

Classify following information as primary or secondary data.

i. Information of attendance of every student collected by visiting every class in a school.

ii. The information of heights of students was gathered from school records and sent to the head office, as it was to be sent urgently.

iii. In the village Nandpur, the information collected from every house regarding students not attending school.

iv. For science project, information of trees gathered by visiting a forest.

For class interval 20-25 write the lower-class limit and the upper-class limit.

If class mark is 10 and class width is 6 then find the class.

Complete the following table.