S1; changing the variance and the sd without caluclating

in some papers they sometimes say if another 2 values are added, what effect would this have on the mean and standard deviation/variance

how do u work it

thanks

Reply 1

gorgeousguy

If they are both bigger than the mean they will increase it. If they are further away from the mean than the standard deviation, they will increase this as well. All they want are general comments like that for this type of question.

Reply 2

magnum

for example..

If the mean was '100'

and 90 and 110 were added.

It would not affect the mean as they are both '10' away from the mean..
10 below and 10 above 100.

Reply 3

gorgeousguy

magnum

for example..

If the mean was '100'

and 90 and 110 were added.

It would not affect the mean as they are both '10' away from the mean..
10 below and 10 above 100.

However it may effect the standard deviation, depending on how spread out the original data was.

Reply 4

Neo1

IF you add to extra values the standard deviation and variance doesnt get affected!.. it wont increase or anything as mrssmiley says...if im not wrong..!

From John

Reply 5

Neo1

IF you add to extra values the standard deviation and variance doesnt get affected!.. it wont increase or anything as mrssmiley says...if im not wrong..!

From John

Reply 6

gorgeousguy

The variance is a measure of spread. Therefore is you add more values which change this, the standard deviation changes. At least thats what ive been taught.

Reply 7

Neo1

mrsmiley

The variance is a measure of spread. Therefore is you add more values which change this, the standard deviation changes. At least thats what ive been taught.