The marks obtained by 10 students in a class-test were as follows :
38, 41, 36, 31, 45, 38, 27, 32, 29, 39
Find :
(i) the mean of their marks;
(ii) the mean of their marks, when the marks of each student are increased by 2;
(iii) the mean of their marks, when 1 mark is deducted from the marks of each student;
(iv) the mean of their marks, when the marks of each student are halved.

Question

The marks obtained by 10 students in a class-test were as follows :
38, 41, 36, 31, 45, 38, 27, 32, 29, 39
Find :
(i) the mean of their marks;
(ii) the mean of their marks, when the marks of each student are increased by 2;
(iii) the mean of their marks, when 1 mark is deducted from the marks of each student;
(iv) the mean of their marks, when the marks of each student are halved.

KnowledgeBoat · Accepted Answer

(i) We know that, Mean = We have, Hence, mean of marks = 35.6. (ii) If 2 marks are added to each student, the mean also increases by 2. New mean = 35.6 + 2 = 37.6 Hence, mean when marks are increased by 2 = 37.6 (iii) If 1 mark is deducted to each student, the mean also decreases by 1. New mean = 35.6 - 1 = 34.6 Hence, mean when 1 mark is deducted = 34.6 (iv) If the marks of each student are halved, the mean is also halved. New mean = = 17.8 Hence, mean when marks are halved = 17.8

Mathematics

Measures of Central Tendency

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