The mean and standard deviation of 100 observations were calculated as 40 and '5.1', respectively by a student who took by mistake 50 instead of 40 for one observation. What are the correct mean and standard deviation?

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

Suppose that mean and standard deviation of 6 observations are 8 and 4 respectively . Let each observation be multiplied by 3. Find the new mean of the resulting observations

The mean and standard deviation of six observations are 8 and 4, respectively. If each observation is multiplied by 3, find the new mean and new standard deviation of the resulting observations.

The mean and S.D. 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. If wrong item is omitted.

The mean and S.D. 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.if it is replaced by 12.

Suppose that mean and standard deviation of 6 observations are 8 and 4 respectively . Let each observation be multiplied by 3 Find the standard deviation of the resulting observations.

(b)The mean and standard deviation of 6 observations are 8 and 4 respectively.If each observation is multiplied by 3,find the new mean and new standard deviation of the resulting observations.

The mean and S.D. of a group of 100 observations were found to be 20 and 3 respectively. Later on its was found that three observations were incorrect which were recorded as 21,21 and 18 find the mean S.D. if the incorrect observations were omitted.

Calculate the mean variance and standard deviation of the following frequency distribution.