Question

How many would we need to call in order to estimate p with 95% confidence, to within 0.025?

Answer 1

Here we have to find Sample size (n) {How many we need to call },

So to find sample size we need to use below formula

(If we have no prior estimate of p, so in this case we use given formula)

So we have given that,

Zc (Z critival value) = 1.96

E = 0.025

So we put the values in given formula,

n= 1/4 * (1.96/0.025)^2

= 0.25* (78.4)^2

= 0.25*78.4*78.4

=1536.64

n = 1537  ( rounded to next whole number)

So we need sample size of 1537 to call in order to estimate p.