Based on historical data at Oxnard college, they believe that \( 42 \% \) of freshmen do not visit their advisors regularly. For this year, you would like to obtain a new sample to estimate the proportion of freshmen who do not visit their advisors regularly. You would like to be \( 90 \% \) confident with a margin of error of \( 4 \% \). Assume the conditions are met and use the appropriate formula to determine how many people you would need to sample. \( n=412 \) Show your steps on paper or in the add work box: Question Help:

\begin{tabular}{l} Exemplo 1: \( \quad \) IC: Variância Conhecida \\ Um conjunto de 10 suínos da raça Wessex teve um peso médio de 108 kg. \\ Determinar o I.C. para a média de pesos, ao nível de 95\% de confiança, \\ sabendo que eles tem distribuiçâo normal com desvio-padrão 10 kg. \\ \hline Solução: \\ \hline \begin{tabular}{l}\( \sigma=10 \mathrm{~kg} \) \\ \( n=10 \) \\ \( \bar{y}=108 \mathrm{~kg} \) \\ \( 1-\alpha=0,95 \) \\ \( z=1,96 \) \\ \hline\end{tabular} \\ \hline\end{tabular}

Propecties of Binomal Dost \( X \sim B(n, p) \) \( P\left(X=x_{1}\right)=\binom{n}{x} p^{x}(1-p)^{n x} \)

정규분포 \( N(m, 20) \) 을 따르는 모집단에서 표본 900 개를 임의추출하여 표본평균을 측정하였더니 \( \bar{x} \) 이었다. 이때 모평균 \( m \) 에 대한 신뢰도 \( 99 \% \) 의 신뢰구간의 길이를 구하여라.

How many apps? According to a website, the mean number of apps on a smartphone in the United States is 95 . Assume the number of apps is normally distributed with mean 95 and standard deviation 25 . Part: \( 0 / 2 \) Part 1 of 2 (a) What proportion of phones have more than 135 apps? Round the answer to four decimal places. The proportion of phones that have more than 135 apps is

전구를 만드는 A 공장에서 400 개의 전구를 임의로 추출하여 전구의 수명을 조사한 결과 평균이 500 시간이고 표준편차가 40 시간이었을 때, 이 공장 전구의 평균 수명 \( m \) 에 대한 신뢰도 \( 95 \% \) 의 신뢰구간을 구하여라.