For a group of 200 students the mean and S.D of marks obtained by them were found to be 40 and 15 respectively.Later on,it was found that the score 23 was misread as 32.Find the correct mean and correct S.D

For a group of 200 candidates the mean and S.D. were found to be 40 and 15 respectively. Later on it was found that the score 43 was misread as 34. Find the correct mean and correct S.D.

The mean and standard deviation of a group of 100 observations were found to be 20 and 3, respectively. Later on it was found that three observations were incorrect, which were recorded as 21, 21 and 18. Find the mean and standard deviation if the incorrect observations are omitted.

The mean and SD of 20 items were found to be 12.5 and 2.1 resp.After that,one item of 23 being added: find the AM and SD of 21 items

Find the Mean and S.D. of first n natural numbers

The mean and S.D. of sample of size 10 were found to be 9.5 and 2.5 respectively. Later on an additional observation became available. This was 15 and was included in the original sample. Find the mean and S.D. of the 11 observations.

The mean and S.D. of a sample of size 10 were found to be 9.0 and 2.0 respectively. Later on, an additional observation 25 was included in the original sample. Find the mean and S.D. of the final 11 observations.

The mean and the standard deviation of a characteristic of 100 items were found to be 60 and 10 respectively. At the time of calculations, two items were wrongly take as 5 and 45 instead of 30 and 20. Calculate the corrected mean and corrected standard deviation.

The mean and S.D. of 20 items were found to be 12 and 6 respectively. On checking it was discovered that items which should correctly read as 11 and 21 had been wrongly taken as 15 nd 27 respectively. Find the correct values of mean and S.D.

A student obtained the mean and standard deviation of 100 observations as 40 and 5.1 respectively. It was later found that he had wrongly copied one observation as 50, the correct figure being 40. Calculate the correct mean and correct standard deviation.