What precautions should be taken while using secondary data?

What methods can be adopted for collecting primary data. Name these methods.

Write any three features of a good questionnaire?

What are secondary data?

Write down the sources of secondary data.

When are secondary sources of data usually used?

What precautions should be taken while using secondary data?

Name any three statistical tools.

What is a questionnaire?

Differentiate between Primary Data and Secondary Data.

Write down the essential qualities of a good questionnaire.