Calculating the standard deviation for the mean difference

[GMartel]

Hi,

Is it possible to calculate the standard deviation of a mean difference, knowing only the mean and SD for instrument 1 and mean and SD for instrument 2 (paired data)? Eg. Mean1=785 (SD1=337), mean2=897 (SD2=444). The mean difference is -112, but I do not have the SD of the mean difference. This is for meta-analysis purposes, where individual papers have provided incomplete data. Thanks!

GM

[PaigeMiller]

Here's the formula: https://stattrek.com/sampling/difference-in-means.aspx

[GMartel]

Thank you!

Now I understand that this assumes the two samples are independent of one another. Can one assume that this applies to paired data?

[PaigeMiller]

Yes, this is for independent samples. The formula for paired samples is different.