Answers

2016-02-22T17:06:20+05:30
∑x/36 =12
∑x = 36 × 12 = 432

∴ incorrect value = 432

correct value = incorrect value ∑x - incorrect value + correct value
                     = 432 - 47 + 74
                       = 459

so the correct mean = ∑x / n = 459/36=12.75
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2016-02-23T16:36:53+05:30
Mean=sum of all observations ÷no.of.observations
12=sum of all observations ÷36
12×36=sumof all observations
432=incorrect mean
432+(74-47)=459=correct sum of all numbers 459/36=correct mean 12.75=correct mean
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