Question

1200 employees of a company were surveyed to find out whether they were satisfies with the company's insurance policy. the survey showed that 80% of the respondents were not satisfied with the policy.
the standard error of the proportion is _%
the number of people who are satisfied with the policy if between _% and _%
All answers are appreciated thank you

Answer 1

Answer with explanation:

Sample Size = 1200

it is also given that 80% of the respondents were not satisfied with the policy,Means 20% of the respondents were satisfied with the policy.

80% of 1200=960

20% of 1200 =240

Standard error of the proportion

  $=\sqrt\frac{P\times(1-P)}{N}}\\\\=\sqrt{\frac{\frac{960}{1200} \times \frac{240}{1200}}{1200}}\\\\=\sqrt{\frac{\frac{1}{5}\times\frac{4}{5}}{1200}}\\\\=\sqrt{\frac{1}{7500}}\\\\=\sqrt{0.000134}\\\\=0.0115758$

= 0.0115 (Approx)

=0.0115×100

=1.15%

→→20% of the respondents are satisfied with the policy.

So, the number of people who are satisfied with the policy is between 20-1.15=18.85% and 20+1.15=21.15% that is (18.85%,21.15%).

Answer 2

The standard error of proportion is +/- 1.15.The number of people who are satisfied with the policy is between 18.85% and 21.15% <span />