4. Sospechamos que nuestro cromatógrafo está estropeado, y queremos determinar si los resultados que nos proporciona son lo suficientemente precisos. Para ello, realizamos una serie de 8 mediciones del contenido de una solución de referencia que, sabemos, contiene 90 ml . de un determinado compuesto. Los resultados que obtenemos en ml. son: \( 93.3 \quad 86.890 .490 .194 .9 \quad 91.6 \quad 92.3 \quad 96.5 \) Construir un intervalo de confianza al nivel de \( 95 \% \) para la media poblacional. ¿Qué conclusiones podemos realizar?

\begin{tabular}{l} In a re-analysis of published studies, Twenge and Im (2007) found that for the \\ time period 1958-2001, the need for social approval of people in the United \\ States was negatively correlated with the U.S. divorce rate during the same \\ period (the correlation coefficient was -0.38). This correlation means that _- \\ divorce rates were high when the need for social approval was high \\ the need for social approval spurred people to divorce \\ the need for social approval prevented people from seeking divorce \\ divorce rates were low when the need for social approval was high \\ \hline\end{tabular}

Using the Pearson correlation coefficient to analyze the relationship between two variables is only appropriate if the variables are__ variables. one scale and one nominal ordinal nominal scale

In a hypothesis test for the Pearson correlation coefficient, the null hypothesis is rejected when \( r=0 \) \( r<\alpha \) \( p<\alpha \) \( p=0 \)

The first step involved in calculating the Pearson correlation coefficient is to sum all the scores square all the scores calculate the standard deviation for each variable

8. For a class project, a political science student at a large university wants to estimate the percent of students who are registered voters. She surveyed 190 students and finds that 80 are registered voters. Compute a \( 98 \% \) confidence interval for the true percent of students who are registered voters and interpret the confidence interval. (Round the answers to 4 decimal places.)