Question

a reseaech insitute poll asked respondents if they acted annoy a bad driver. in thw poll n=2331 and x=1058 who said they honkey. so the best estimate of the true proportion of all such respondent is p=0.454. use a 99 % confudence level. (za/2 = 2.576)

calculate margin of error

Answer 1

Solution :  

Given that,

n = 2331

x = 1058

Point estimate = sample proportion = = x / n = 1058 / 2331 = 0.454

1 - = 1 - 0.454 = 0.546

At 99% confidence level the z is ,

= 1 - 99% = 1 - 0.99 = 0.01

/ 2 = 0.01 / 2 = 0.005

Z_/2 = Z_0.005 = 2.576

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

= 2.576 * (((0.454 * 0.546) / 2331)

Margin of error = E = 0.027