# Thread: Comparing small differences in mean values while standard deviation is high...

1. ## Comparing small differences in mean values while standard deviation is high...

Hi,

I'm sorry if this is a basic question and I'm also sorry for my cumbersome problem description. I guess I'm lacking some serious fundamentals right here and I'm at a point where I need some external kick-off.

Following Scenario:
We are employing method A and method B onto test system v, w, x, y, z... . Getting data points is quite resource intensive so we only have few (in this case 5) data points. We get a mean value of 1.00 (with a standardard deviation of 0.10) for method A and a mean value of 1.04 (as well with a standard deviation of 0.10). Obviously p-value testing would tell us that we can't say that the mean value of method B is significantly higher than for method A. So we move on and take another five data points... . For the whole 10 data points the mean value for method A is still 1.00 (with a standardard deviation of 0.10) and for method B still 1.04 (with a standardard deviation of 0.10). p-value would still tell us that we can't say that the mean value of method B is significantly higher than for method A. But intuitively you would except this statement to be more true after 10 data points... But how would a statistican account for this?

2. ## Re: Comparing small differences in mean values while standard deviation is high...

hi,
the relatively high standard deviation in each group is caused by the different test systems : v,w...? Now, that you have a pair of data for each, you could compare the differences for each system to see how much variation they have between method A and B.

regards

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