Mean of 50 observations was found to be 80.4. but later on, it was discovered that 96 was misread as 69 at one place. Find the corect mean.

The mean of marks scored by 100 students was found to be 40, later on, it was discovered that a score of 53 was misread as 83. find the correct mean.

The mean of 40 numbers was found to be 35. Later on, it was detecte that a number 56 was misread as 36. find the correct mean of the given numbers.

The mean of 100 items was found to be 64. later on, it was discovered that two itens were misread as 26 and 9 instead of 36 and 90 respectively. Find the correct mean.

The mean of 200 items was 50. later on, it was discovered that the two items were misread as 92 nd 8 instead of 192 and 88, find the correct mean.

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 standard deviation of 20 observations are found to be 10 and 2. respectively. On rechecking, it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation in each of the following cases: (i) If wrong item is omitted. (ii) If it is replaced by 12.

The mean of 5 observation is 4.4 and their variance is 8.24 . If three of the observations are 1,2 and 6, find the other two observations

From a frequency distribution consisting of 18 observations, the mean and the standard deviation were found to be 7 and 4 respectively. But on comparison with the original data, it was found that a figure 12 was miscopied as 21 in calculations. Calculate the correct mean and standard deviation.