Respuesta :
Answer:
a. p=0.5184
b. All requirements (random, normal, independent) are satisfied.
c. A) We are 95% confident proportion of adults in the country who believe that televisions are a luxury they could do without is between 0.485 and 0.5493.
Step-by-step explanation:
A point estimate for the population proportion of adults in the country who believe that televisions are a luxury they could do without can be calculated from the sample proportion.
The sample proportion is p=0.5184.
[tex]p=X/n=522/1007=0.5184[/tex]
The requirements for constructing a confidence interval about p are:
- Random: the sample is random, so it is satisfied.
- Normal: the values for np and n(1-p) have to be equal or greater than 10. This is satisfied (np=522, n(1-p)=485).
- Independent: as the sample is less than 10% of the population and the sampling is random, this is also satisfied.
We have to calculate a 95% confidence interval for the proportion.
The critical z-value for a 95% confidence interval is z=1.96.
The standard error of the proportion is:
[tex]\sigma_p=\sqrt{\dfrac{p(1-p)}{n}}=\sqrt{\dfrac{0.5184*0.4816}{1007}}\\\\\\ \sigma_p=\sqrt{0.000248}=0.0157[/tex]
The margin of error (MOE) can be calculated as:
[tex]MOE=z\cdot \sigma_p=1.96 \cdot 0.0157=0.0309[/tex]
Then, the lower and upper bounds of the confidence interval are:
[tex]LL=p-z \cdot \sigma_p = 0.5184-0.0309=0.4875\\\\UL=p+z \cdot \sigma_p = 0.5184+0.0309=0.5493[/tex]
The 95% confidence interval for the population proportion is (0.4875, 0.5493).