The mean of a set of 60 observations is 50. It was later discovered that two observations, 55 and 57, were incorrectly recorded as 35 and 37. What is the correct mean?
48.7
49.2
49.8
50.4
To find the correct mean, we need to adjust the two incorrectly recorded observations and recalculate the mean.
The sum of the original 60 observations is 50 60 = 3000.
We need to subtract the incorrect values (35 and 37) and add the correct values (55 and 57) to the sum.
Corrected sum = (3000 - 35 - 37) + 55 + 57 = 3000 - 35 - 37 + 55 + 57 = 3040.
The correct mean is the corrected sum divided by the number of observations (60).
Corrected mean = 3040 / 60 = 50.666666666666664.
Therefore, the correct mean is approximately 50.666666666666664.
Among the given options, 50.4 is the closest to the correct mean.
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