SD and Mean

In some of questions of mean and standard deviation they said without further calculation
What will effect on mean and SD

In most of cases some time mean increases and some times decreases

What will effect on SD if mean increases and what will effect if decreases

If the values have had numbers added or taken away then no effect on the SD. Addition and subtraction has no effect on the SD but multiplying / dividing does.

In some of questions of mean and standard deviation they said without further calculation
What will effect on mean and SD

In most of cases some time mean increases and some times decreases

What will effect on SD if mean increases and what will effect if decreases

Have seen this type of question a few times. If a new value is added to the set of data then if you think about how the mean is calculated if it's above the original mean the mean will increase if it's below the original mean then the new mean would be lower. If it equals the mean then there would be no change.


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