¿Qué supuesto es fundamental para * 1 punto realizar la prueba \( t \) de Student para muestras independientes? \( \begin{array}{l}\text { Las varianzas de ambas muestras deben } \\ \text { ser iguales. }\end{array} \) \( \begin{array}{l}\text { Ambas muestras deben tener el mismo } \\ \text { número de observaciones. }\end{array} \) Los datos deben ser ordinales.

Coffee consumption has been found to be negatively correlated with amount of sleep, with a correlation coefficient of 0.5 . How much can the coffee consumption account for the variance of amount of sleep? \( 0.5 \% \) \( 50 \% \) \( 0.25 \% \) \( 25 \% \)

Many investors and financial analysts believe the Dow Jones Industrial Average (DJIA) gives a good barometer of the overall stock market. On January \( 31,2006,9 \) of the 30 stocks making up the DJIA increased in price (The Wall Street Journal, February 1, 2006). On the basis of this fact, a financial analyst claims we can assume that \( 30 \% \) of the stocks traded on the New York Stock Exchange (NYSE) went up the same day. A sample of 76 stocks traded on the NYSE that day showed that 10 went up. You are conducting a study to see if the proportion of stocks that went up is is significantly less than 0.3 . You use a significance level of \( \alpha=\ldots 2 \). What is the test statistic for this sample? Use \( \hat{p} \) rounded to 4 decimal places. (Report answer accurate to 4 decimal places.) test statistic =

Which of these values of the correlation coefficient indicates the weakest relationship between two variables? -0.30 -0.18 0.03 0.42

Test the claim that the proportion of people who own cats is significantly different than \( 10 \% \) at the 0.2 significance level. The null and alternative hypothesis would be: \( H_{0}: p=0.1 \quad H_{0}: p=0.1 \quad H_{0}: \mu=0.1 \quad H_{0}: \mu=0.1 \quad H_{0}: p=0.1 \quad H_{0}: \mu=0.1 \) \( H_{1}: p \neq 0.1 \quad H_{1}: p<0.1 \quad H_{1}: \mu \neq 0.1 \quad H_{1}: \mu>0.1 \quad H_{1}: p>0.1 H_{1}: \mu<0.1 \) The test is: right-tailed left-tailed two-tailed Based on a sample of 700 people, \( 8 \% \) owned cats The test statistic is: \( -\quad \) This is not a decimal or integer value. (to 4 decimal places) The p-value is:

Many investors and financial analysts believe the Dow Jones Industrial Average (DJIA) gives a good barometer of the overall stock market. On January 31, 2006, 9 of the 30 stocks making up the DJIA increased in price (The Wall Street Journal, February 1, 2006). On the basis of this fact, a financial analyst claims we can assume that \( 30 \% \) of the stocks traded on the New York Stock Exchange (NYSE) went up the same day. A sample of 76 stocks traded on the NYSE that day showed that 10 went up. You are conducting a study to see if the proportion of stocks that went up is is significantly less than 0.3 . You use a significance level of \( \alpha=0.002 \). What is the test statistic for this sample? Use \( \hat{p} \) rounded to 4 decimal places. (Report answer accurate to 4 decimal places.) test statistic \( =-3.198^{\circ} \times \)