Thursday, August 23, 2012
Statistics FAIL: Zero Percent of Black Voters Support Obama
A poll released earlier today from NBC/Wall St Journal is reporting Romney at 0% support among black voters and Obama at 94%. The sample polled 1000 people, 12% of which were black. Meaning a meager 120 blacks were polled.
In 2008, black voters consisted of 13% of the electorate that consisted of more then 130 million voters. Likewise, blacks make up 13.1% of the total US population according to the most recent census data. This leads to the conclusion that black representation in the presidential election mirrors that of the population overall.
Right off, then, we can see the NBC/WSJ poll has under sampled blacks by roughly 8%.
In 2008, 96% of black voters cast their ballots for Obama, but instead of reporting the poll as Obama losing support among blacks, its reporting the statistical anomaly regarding Romney's level of support. Are we truly to believe he has no support at all among blacks?
Taking this data and calculating the probability that zero percent of black voters sampled in the NBC/WSJ poll is under reported, at a 95% significance level, we find there is a 98.8% probability the sample is inaccurate. If we reverse the test and determine the probability the Obama's drop in support is more inaccurate, we find a much lower probability of that being true.
But, yeah, let's run with Romney's support among black at 0% as the headline, anyway.