Class 11 Economics Short Questions and Answers: Organisation of Data - 2

Q.16. Define series.
Ans. A series, in statistics, is a set of observations or attributes arranged according to a definite order (for example, in ascending or descending order). For instance, ages 18, 20, 22, 24 arranged from smallest to largest form a series.
Q.17. State one feature of inclusive series?
Ans. In an inclusive series, both the lower and the upper class limits are treated as part of the class interval; the upper limit is not excluded. For example, the class 10-19 includes both 10 and 19 as members of that class.
Q.18. What is an open-end series?
Ans. An open-end series is one in which either the lower limit of the first class or the upper limit of the last class is not specified. Examples are classes denoted as "Less than 20" or "70 and above", where one end is open.
Q.19. Write one function of tally marks.
Ans. Tally marks provide a quick visual method of counting and recording frequencies by grouping observations in fives; they speed up counting and reduce errors when collecting raw data.
Q.20. What are the two ends of a class called?
Ans. The two ends of a class are called the class limits, namely the lower class limit and the upper class limit.
Q.21. Give another name for class interval.
Ans. Class width (or class size) is another name for class interval; it indicates the extent of the class and is found from the difference between the upper and lower limits of the class.
Q.22. Define range.
Ans. The range is the difference between the largest and the smallest value of a variable. In formula form: Range = Maximum value - Minimum value. For example, if the highest value is 90 and the lowest is 30, the range = 60.
Q.23. Write a short note on 'range'.
Ans. Range measures the spread or dispersion of data by showing the difference between the highest and lowest observations. A large range means values are widely spread, while a small range means they are closely clustered. Range is simple to compute but sensitive to extreme values. When class intervals are equal, range can also be expressed as: Range = Number of Classes × Class Interval.
Q.24. When is frequency distribution with unequal classes more appropriate?
Ans. Frequency distribution with unequal class intervals is appropriate when observations are not evenly spread and tend to concentrate around certain values, or when one wants class marks to coincide with central values of dense regions. Unequal classes help to present dense areas in finer detail while grouping sparse areas into wider classes.
Q.25. Why is there no class mark in a discrete frequency distribution?
Ans. A discrete variable takes only distinct integral values, so data are presented as a frequency array listing each value and its frequency rather than as grouped classes. Because there are no class intervals in such a distribution, there is no class mark (mid-point) to compute.
Q.26. What is the principal objective of classification of data?
Ans. The principal objective of classification is to organise raw data systematically so that its main features become clear and easier to interpret. Classification summarises information, reveals patterns and relationships, facilitates comparison, and saves time and effort in analysis.