See if incorrect mean is 40 and since Mean = (sum of Xi)÷N I.e. sum of Xi =Mean × N = 40×100 =4000 Now subtract incorrect observation and add correct observation into this sum of observation I.e. (4000 - 50 + 40) =3990 Correct mean = 3990 ÷ 100 = 39.9 In the same manner From SD calculate variance and then subtract 50² and add 40² Then from new corrected variance calculate SD.

CA Foundation doubt

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Asked by Minakshi21 Nov 2024644 views

1 answer

Tushar · 21 Nov 2024
See if incorrect mean is 40 and since Mean = (sum of Xi)÷N I.e. sum of Xi =Mean × N = 40×100 =4000 Now subtract incorrect observation and add correct observation into this sum of observation I.e. (4000 - 50 + 40) =3990 Correct mean = 3990 ÷ 100 = 39.9 In the same manner From SD calculate variance and then subtract 50² and add 40² Then from new corrected variance calculate SD.

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