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# Excel standard deviation

Posted on 2014-04-09

Experts:

Maybe I need some more coffee this morning... I'd like to get some pointers for assessing quality of some data. I'll try to keep it simple.

Let's say I have a mean value which ranges (usually) between 1550 and 1650 (unit is not important here).

Also, I have "uncertainty" values (calculated based on partial derivatives) which may range between +/- 6 to 8.

For sake of argument, let's now assume that I have the following data sets:

Scenario 1:

Mean value = 1600

Uncertainty value = +/- 7

Thus, min = 1593 and max 1607

Scenario 2:

Mean value = 1570

Uncertainty value = +/- 8

Thus, min = 1562 and max 1578

Scenario 3:

Mean value = 1650

Uncertainty value = +/- 8

Thus, min = 1642 and max 1658

I'd like to put these values into perspective of "quality" (i.e., comparing the three different scenarios). Given that I have a fairly consistent range for both mean values and min/max values, the proportional quality (e.g., min/mean or max/mean) may not tell a good "story" when those values will change.

That said, given these aforementioned information, does anyone one of a good way to suggest "quality" of data where slight changes in mean/min/max ranges result in different interpretation(s)?

Ideally, I'd like to plot these data (maybe on normal curve)... I'm open to suggestions though.

I hope this makes sense... again, I'm trying to keep it simple here.

Thanks,

EEH