Mathematics
Explain the meaning of the following terms:
(i) variate
(ii) class size
(iii) class mark
(iv) class limits
(v) true class limits
(vi) frequency of a class
(vii) cumulative frequency of a class.
Answer
(i) Variant — A particular value of a variable is called variate.
(ii) Class size — The difference between the actual upper limit and the actual lower limit of a class is called its class size.
(iii) Class mark — The class mark of a class is the value midway between its actual lower limit and actual upper limit.
(iv) Class limits — In the frequency table the class interval is called class limits.
(v) True class limits — In a continuous distribution, the class limits are called true or actual class limits.
(vi) Frequency of a class — The number of tally marks opposite to a variate is its frequency and it is written in the next column opposite to tally marks of the variate.
(vii) Cumulative frequency of a class — The sum of frequency of all previous classes and that particular class is called the cumulative frequency of the class.
Related Questions
Using class intervals 0-4, 5-9, 10-14, ……. construct the frequency distribution for the following data :
13, 6, 10, 5, 11, 14, 2, 8, 15, 16, 9, 13, 17, 11, 19, 5, 7, 12, 20, 21, 18, 1, 8, 12, 18.
Given below are the marks obtained by 27 students in a test:
21, 3, 28, 38, 6, 40, 20, 26, 9, 8, 14, 18, 20, 16, 17, 10, 8, 5, 22, 27, 34, 2, 35, 31, 16, 28, 37.
(i) Using the class intervals 1-10, 11-20 etc. construct a frequency table.
(ii) State the range of these marks.
(iii) State the class mark of the third class of your frequency table.
Fill in the blanks :
(i) The number of observations in a particular class is called ………. of the class.
(ii) The difference between the class marks of two consecutive classes is the ………. of the class.
(iii) The range of the data 16, 19, 23, 13, 11, 25, 18 is ………. .
(iv) The mid-point of the class interval is called its ………. .
(v) The class mark of the class 4 – 9 is ………. .
The marks obtained (out of 50) by 40 students in a test are given below:
28, 31, 45, 03, 05, 18, 35, 46, 49, 17, 10, 28, 31, 36, 40, 44, 47, 13, 19, 25, 24, 31, 38, 32, 27, 19, 25, 28, 48, 15, 18, 31, 37, 46, 06, 01, 20, 10, 45, 02.
(i) Taking class intervals 1 – 10, 11 – 20, .., construct a tally chart and a frequency distribution table.
(ii) Convert the above distribution to continuous distribution.
(iii) State the true class limits of the third class.
(iv) State the class mark of the fourth class.