import numpy as np
treat = 330.8 treat_se = 99.7 placebo = 188.1 placebo_se = 55.5 n = 15
Formula for SE of difference:
and $SE = SD/\sqrt{n}$, so for this example:
SE_diff = np.sqrt(99.7**2 + 55.5**2) SE_diff
114.10670444807351
Hence, a 95% confidence interval for the difference would be:
d = treat-placebo d - 2*SE_diff, d + 2*SE_diff
(-85.513408896147013, 370.91340889614708)
Which, given n=15 and the variability, is pretty unccertain.