Question

The mean and standard deviation of 15 observations are found to be 10 and 5 respectively. On rechecking it was found that one of the observation with value 8 was incorrect Calculate the correct mean and standard deviation if the correct observation value was 23?​

Answer 1

Answer:

the mean would be 11

Step-by-step explanation:

10 x 15=150

150 is the total amount of the observations added up.

150-8=142

you do this because 8 was the incorrect observation then you add 23.

165 divided by 15=11

Answer 2

Answer:

The required mean of the observation is 11

Step-by-step explanation:

we know mean = summation of total observations / values

therefore the total summation = 10 x 15 = 150

Since, 8 is the wrong observation

therefore the correct summation excluding 8 is = 150 - 8 = 142

and add 23, because it is the correct value

therefore, summation = 142 + 23 = 165

now the correct mean = 165 / 15 = 11

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