Question

In a survey of 310 registered voters, 164 of them wished to see Mayor Waffleskate lose her next election. Construct a 99% confidence interval for the proportion of registered voter who want to see Mayor Waffleskate defeated

Answer 1

Solution :

Given that,

Point estimate = sample proportion = = x / n = 164 / 310 = 0.529

1 - = 1 - 0.529 = 0.471

Z/2 = 2.576

Margin of error = E = Z / 2 * (( * (1 - )) / n)

= 2.576 * (((0.529 * 0.471) / 310)

Margin of error = E = 0.073

A 99% confidence interval for population proportion p is ,

- E < p < + E

0.529 - 0.073 < p < 0.529 + 0.073

0.456 < p < 0.602

The 99% confidence interval for the population proportion p is : 0.456 , 0.602