Question

We want to estimate the proportion of residents of Vancouver Island that are in favour of restricting BC ferries travel to essential services only during the COVID-19 pandemic. How many residents should be sampled to estimate the true proportion within 4% with a 98% confidence?

Answer 1

Solution :

Given that,

= 0.5

1 - = 1 - 0.5 = 0.5

margin of error = E = 4%= 0.04

At 98% confidence level the z is ,

= 1 - 98% = 1 - 0.98 = 0.02

/ 2 = 0.02 / 2 = 0.01

Z/2 = Z0.01 = 2.326

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

= (2.326 / 0.04)2 *0.5*0.5

= 845

sample size = 845