Chapter 15 Statistics Ex 15.1

Rajasthan Board RBSE Class 9 Maths Solutions Chapter 15 Statistics Ex 15.1

Question 1.
What are primary and secondary data Differentiate them?
Solution.
When an investigator collects data himself with a definite plan or design in his/her mind is called primary data.
Data which are not originally collected rather obtained from published or unpublished source are known as secondary data.

Question 2.
Name the different methods of collecting primary data.
Solution.

1. Direct personal investigation
2. Indirect investigation
   • Schedules to be filled in by enumeration.
   • Information through questions are to be filled in by informants.
   • Information through local sources.
   • Indirect oral investigation through experts.