Statistics - Solutions

 CBSE Class 9 Mathematics

NCERT Solutions
(Ex. 14.1)

1. Give some examples of data that you can collect from your day to day life.

Ans. Some examples of data that we can gather from our day to day life are:
(i) Number of students in our class.
(ii) Number of fans in our school.
(iii) Electricity bills of our house for last two years.
(iv) Election results obtained from television or newspapers.
(v) Literacy rate figures obtained from Educational Survey.
(vi) Heights of 20 students of our class.
(vii) Maximum temperatures of the days of a particular week from television.
(viii) Number of members in the families of your locality from a record.
(ix) Distances from the school of the homes of ten students.

2. Classify the data in Q.1 above as primary or secondary data.

Ans. Primary data: When the information was collected by the investigator herself or himself with a definite objective in her or his mind, the data obtained is called Primary data. These types of data are original in character and collected for the first time for their own use.

Above mentioned (i), (ii), (iii), (iv) and (ix) are the examples of primary data.

Secondary data: When the information was gathered from a source (like newspapers, television or some other records) which already had the information stored is called Secondary data. Such data has been collected by someone else in another context needs to be used with great care. These data are collected for a purpose other than that of original investigator.

Above mentioned (iv), (v), (vii) and (viii) are the examples of secondary data.