Q6 of 26 Page 14

In a group of 10 students, marks obtained in a subject are as follows: 23, 22, 45, 38, 49, 23, 45, 10, 45, 39. Find the following:
(i) Mean marks of class
(ii) Median marks of class
(iii) Modal marks of class

To Find:

(i) Mean marks of class


(ii) Median marks of class


(iii) Modal marks of class


Given: Marks obtained


Concept Used:



Median = Middle term


Mode = Observation is occurring the most number of times.


Explanation:


Sum of observations = 23 + 22 + 45 + 38 + 49 + 23 + 45 + 10 + 45 + 39 = 345


Number of observations = 10



Arranging the observations in increasing order,


10, 22, 23, 23, 38, 39, 45, 45, 45, 49


As the number of terms are even, median will be the average of


Median


Median = 38.5


Mode = Observation that occurs the most number of time = 45(3 times)


Therefore,


Mean = 33.9


Median = 38.5


Mode = 45


More from this chapter

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4

Write the class mark of the class 130-150.

 5

Let l be the lower-class limit of a class-interval in a frequency distribution and m be the mid-point of the class. Then, find the upper-class limit f.

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The blood groups of 30 students of class VIII are recoded as follows:

A, B, O, O, AB, O, A, O, B, A, O, B, A, O, O, A, AB, O, A, A, O, O, AB, B, A, O, B, A, B, O


Represent this data in the form of a frequency distribution table. Find out which is the most common and which is the rarest blood group among these students.

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Thirty children were asked about the number of hours they watched T.V. programmes in the previous week. The results were found as follows:

1, 6, 2, 3, 5, 12, 5, 8, 4, 8, 10, 3, 4, 12, 2, 8, 15, 1, 17, 6, 3, 2, 8, 5, 9, 6, 8, 7, 14, 12


(i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5-10.


(ii) How many children watched television for 15 or more hours a week?