Practice with Inference for Proportions Homework
Name: \( \qquad \)
1. A Gallop Poll on energy use asked 512 randomly selected adults if they favored "increasing the use of nuclear power as a major source of energy". Gallop reported that 225 said "Yes". Does this poll give good evidence that fewer than half of all adults favor increased use of nuclear power?
a) Find a \( 90 \% \) confidence interval for the proportion of adults who favor increased use of nuclear power. Be sure to check all assumptions.
ssumptions:
\[
n=512 \quad \hat{p}=\frac{205}{512}=0.4395
\]
dom sample given
is reasonable that the population of adults
at least \( 512(10)=512 \), so our sample
independent
\[
\hat{p}=512(0.4395)=225.024 \quad n(1-\hat{p})=512(1-0.4395)=286.976
\]
since both are \( >10 \), the distribution of \( \hat{p} \) is is normal
\[
\left(\frac{225}{512}\right)+1.65 \sqrt{\frac{0.4395(1-0.4395)}{512}}
\]
we are \( 90 \% \) confident that:
\( 0.4034 \leq P \leq 0.4755 \)
b) Conduct a Hypothesis Test to determine if the proportion of adults who favor increased use of nuclear power is less than \( 50 \% \). Check all assumptions and use \( \alpha=0.05 \).
\( H_{0}= \)