The answer is B. If there ever a question similar to this, just put the equation in graphs calculator and see what the graph look like. I hope this is helpful.

3 0

3 years ago

A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtain

Kamila [148]

Answer:

Step-by-step explanation:

Solution:-

- The sample size = n

- The Error of estimation, E = 0.04

- The confidence level, CI = 99%

What size sample should be obtained when she uses previous estimate of p = 0.52?

- We are given the sample proportion p = 0.52, the required sample size is a function of confidence value and error of estimation (E):

$n = p*( 1 - p ) * (\frac{Z-critical}{E})^2$

Where,

- The critical value of the confidence level = 99% would be:

significance level ( α ) = 1 - CI = 1 - 0.99 = 0.01

Z-critical = Z_α/2 = Z_0.005 = 2.575

- The required sample size (n) can be calculated:

$n = 0.52*( 1 - 0.52 ) * (\frac{2.575}{0.04})^2\\\\n = 0.2304*(51.5)^2 = 611.0784$

- Hence, the minimum required sample size (n) should be = 612 adults.

- If the preliminary estimate of proportion is missing or not given, we are to assume the proportion p = 0.5.

- Similarly, repeat the calculations for sample size (n) when p = 0.5

$n = 0.5*( 1 - 0.5 ) * (\frac{2.575}{0.04})^2\\\\n = 0.25*(51.5)^2 = 663.0625$

- Hence, the minimum required sample size (n) should be = 664 adults.

5 0

3 years ago