The local newspaper was interested in the proportion of people that would vote in favor of a bond issue to add a new sewage treatment plant. The paper contacted 80 registered voters and found that 26 of them were in favor of the bond issue. Calculate the MARGIN OF ERROR of a 80% confidence interval for the proportion of all registered voters who favor the bond issue. (Give just the margin of error in the form of a proportion to 3 decimal places, do NOT include any symbols or letters).