Question

We want to determine the current percentage of registered voters who support Bruce Wayne for the president of the US. How many registered voter should we survey in order to be 98% confident that the estimated proportion is with three percentage points of the true population proportion of registered voter who support Bruce Wayne for president.

Answer 1

Solution,

Given that,

=  1 - = 0.5

margin of error = E = 0.03

At 98% confidence level

= 1 - 98%

= 1 - 0.98 =0.02

/2 = 0.01

Z/2 = Z0.01  = 2.33

sample size = n = (Z / 2 / E )2 * * (1 - )

= (2.33 / 0.03 )2 * 0.5 * 0.5

= 1508.02

sample size = n = 1509