9 A \( 99 \% \) confidence interval for the mean mass of steel sheets produced in a factory is \( (30.37 \mathrm{~kg}, 32.43 \mathrm{~kg}) \). This interval is based on a random sample of 36 steel sheets. Find a \( 95 \% \) confidence interval for the mean mass of steel sheets, assuming that the masses of steel sheets are normally distributed.

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 =

Select all of the possible null hypotheses from the list below. \( p=0.37 \) \( p>0.84 \) \( p<0.42 \) \( p \neq 0.10 \)

Josie is organizing her ribbons for a craft project. The list shows the length of each of her ribbons. \( 21.5 \mathrm{~cm}, 12.4 \mathrm{~cm}, 30.4 \mathrm{~cm}, 15.3 \mathrm{~cm}, 10.7 \mathrm{~cm}, 7.9 \mathrm{~cm}, 14.6 \mathrm{~cm}, 11.2 \mathrm{~cm} \) What is the median ribbon length? A. 12.4 cm B. 13.0 cm C. 13.5 cm D. 14.6 cm E. 15.5 cm

Use this set of numbers to answer the question. \( \begin{array}{l}4,11,6,9,23,34,6,19 \\ \text { What is the median for this set of numbers? } \\ \text { A. } 6 \\ \text { B. } 10 \\ \text { D. } 14 \\ \text { D. } 16\end{array} \)

Find the mean of: \( 1.8,1.7,1.3,1.1,1.2,1.6,1.8 \) A. 1.6 B. 1.4 C. 1.8 D. 1.1 E. 1.5