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.

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.

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.

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?

In an experiment with 15 observations on x, the following results were available Sigma x^(2)=2830 , Sigma x=170 On observation that was 20, was found to be wrong and was replaced by the correct value 30. Then, the corrected variance is

Two cars A and B travelling with speed 20m/s and 10m/s respectively applied brakes, so that A comes to rest in 15 second and B in 7.5s. From the graph determine which of the two cars travelled further after brakes were applied and by how much distance it travelled?