According to the 2010 Census, 11.4% of all housing units in the United States were vacant. A county supervisor wonders if her county is different from this. She randomly selects 850 housing units in her county and finds that 129 of the housing units are vacant.

a) State the hypotheses.
b) Name the model and check appropriate conditions for a hypothesis test.
c) Draw and label a sketch, and then calculate the test statistic and P-value.
d) State your conclusion.