Question

1. You are given a margin of error as 3 percentage points and a confidence level of 99%. If the sample percentage from a recent poll is 35%, find the minimum sample size to estimate a population proportion.

a.496

b.2579

c.1677

d.248


2. You are given E = 0.020, a confidence level of 90% and a sample proportion of 85% recent survey. Find the minimum sample size to estimate a population proportion.

a.1225

b.259

c.5751

d.863


3. Given n = 875 and p^ = 0.45, find the margin of error E that corresponds to a 95% confidence level

a.0.001

b.0.016

c.0.044

d.0.033

Answer 1

1677

Explanation:

Answer 2

Explanation:

1) p=0.35 and q = 0.65

Std error =
`\sqrt{(0.35*0.65)/(n) }`

Margin of error = 2.58*std error = 3%

i.e.
`2.58*0.477/√(n)= 0.03\\n = 1683\\`

Approximately 1677

2) Same method as above

Margin of error = 1.645 *
`\sqrt{(0.85(0.15))/(n) }`=0.02

Hence n = 863

3) Margin of error = 1.96*
`\sqrt{(0.45(0.55))/(875) }`

=0.0329

=0.033

(option d)