
Not to be a party pooper, or let my personal bias interfere with my analysis, I do have some concerns about the validity of the Nanos poll. The increase in the Liberal support is indeed startling, more so because it is a three day polling average, which means the difference between the Liberal support on Sunday and on Wednesday must be at least 12% in order to account for an increase of 4% over a single day. Similarly, the NDP support must have dropped by approximately 12% over the same time period to explain their sudden drop in support.
Because of the low NDP support initially, this means that at least 1 in 2 NDP supporters on Sunday decided to switch their votes and go with the Liberals instead by Wednesday, dropping the NDP support to around 10%. Does that sound realistic to you?
Mathematically the problem is very interesting since there is no way I can see to determine for certain what the actual daily values that were used to calculate the averages; there are 8 variables and only 4 equations available.
We know that the average of A, B and C must be 28.7, the average of X, Y and Z must be 19.6 while the averages of B,C and D and Y, Z and W must be 32.7 and 15.9 respectively. By arbitrarily choosing a few values for A, B, X and Y we can figure out from there what the remaining values must be. Choosing initial Liberal support of 27 and 28 would mean that the third and fourth days would have Liberal support of 31 and 39 respectively, a shockingly high number for the fourth day. If the NDP support was 20 and 20 for the first two days, then it must be 19 and 9 on the third and fourth days, a shockingly low number. I tried another more reasonable possibility that wound up with Liberal support at 35% and NDP support at 12% but it still requires an unbelievable drop in NDP support.
Try it out for yourself, see if you can find some more reasonable numbers than I did.
