Question

Marks secured by a group of 10 students are as follows : 16, 18, 29, 31, 20, 23, 26, 25, 32, 20 (i) find the mean of the data (ii) if 32 is replaced by 23 in the data, find the new mean. (iii) if each observation in the given data is increased by 5 marks, then what will be the mean

Answer 1

(i) 16+18+29+31+20+23+26+25+32+20 = 240
so, sum of all values = 240
no. of values = 10
Since, Mean = sum of all values/no. of values
So, Mean = 240 / 10
Mean =24

(ii) Now, replacing 32 by 23 , we get
16+18+29+31+20+23+26+25+23+20 = 231
so, sum of all values = 231
no. of values = 10
Since, Mean = sum of all values/no. of values
So, Mean = 231 / 10
Mean =23.1

(iii) 16+18+29+31+20+23+26+25+32+20 = 240
so, sum of all values = 240
no. of values = 10
For each observation in the given data to be increased by 5 marks,we need to add 5 for 10 times
so,now finally sum of all values= 240 + ( 5 * 10 )
=290
Since, Mean = sum of all values/no. of values
So, Mean = 290 / 10
Mean =29