bList1 = [] sList1 = [] sAv = [] sOut = []

for sList in bList:

av = np.average(sList) std = np.std(sList)

for sVal in sList:

if abs(sVal-av) < 2*std: sList1.append(sVal)

else: sOut.append(sVal)

av1 = np.average(sList1) sAv.append(av1) bList1.append(sList1)

print(sAv)

So I have a main list, bList, with list items in it, sList

For each sList in bList,

-> find the mean and standard dev. for that sList

then -> for each item, sVal, in that sList, see if that item meets criteria

if yes -> add to new list, sList1

if no -> add to new list, sOut

-> then find the mean for the newly created sList1, and add that to new list, sAv

in total I should have 13 new means in sAv, instead I have 3300+ lines of data!