xs = []
ys = []
for r in data:
    ys += list(r)
ys.append(None)
xs += [1.3, 1.7]
xs.append(None)
pl.plot([1.3] * len(first), first, 'o', [1.7] * len(second), second, 'o',
    xs, ys)
pl.boxplot(data)
pl.ylim([min(min(first), min(second)) - 0.5, max(max(first), max(second)) +
    0.5])
labels = 'first', 'second'
pl.xticks([1, 2], labels)
pl.show()
How to draw a plot joining points from two measurement times?