NCERT Solutions for Class 9 Maths Chapter 14 - Exercise 14.1 Statistics

Q.1. Give five examples of data that you can collect from your day-to-day life.
Sol. 
Five examples from day-to-day life:

1. Number of students in our class.
2. Number of fans in our school.
3. Electricity bills of our house for last two years.
4. Election results obtained from television or newspapers.
5. Literacy rate figures obtained from Educational Survey

Q.2. Classify the data in Q.1 above as primary or secondary data.
Sol. 
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.
Primary data; (i), (ii) and (iii)
Secondary data; when the information was gathered from a source which already had the information stored, the data obtained is called secondary data
Secondary data; (iv) and (v)

Presentation of Data

• Every group into which the raw data is condensed is called a class-interval.

• In each of these classes, the least number is called the lower-class limit and the greatest number is called the upper-class limit.
• The difference between the upper limit and the lower limit of a class is called its class size.
• The difference between the maximum value and the minimum value of the observation is called the range.
• The class-mark of a class =