The molecular weight data for a polyethylene polymer sample is given and use it to calculate the following:

a) number average molecular weight

b) weight average molecular weight

c) number average degree of polymerization (DP

d) polydispersity index (PDI)

xi wi Molecular Weight Range g/mol 8,00020,000 20,00032,000 32,00044,000 0.05 0.02 0.15 0.08 0.21 0.17 44,00056,000 0.28 0.29 56,000-68,000 0.18 0.23 68,00080,000 0.10 0.16 80,000-92,000 0.03 0.05