Question

The mean, median and modal marks of 100 students were found to be 40, 41 and 43 respectively. Later on it was discovered that a score of 53 was misread as 83. Find the correct mean corresponding to the correct score.

A 39.7 Correct Answer Incorrect Answer
B 55.9 Correct Answer Incorrect Answer
C 63.21 Correct Answer Incorrect Answer
D 79.5 Correct Answer Incorrect Answer
E 60 Correct Answer Incorrect Answer

Solution

Mean = 40 Median = 41 Mode = 43 n = 100 a score of 53 was missed as 83 X = 40 =`(sumX_i)/(n)` `40 = (sumX_i)/(100)` ` ` `sumX_i = 40 xx100 = 400` `` correct`sumX_i = 4000 - 83 + 53` ` = 3970` `correct X = 3970/100` `=39.7 ` ` `

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