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Use data on college students collected from the American College Health Association-National College Health Assessment survey \(^{18}\) conducted in Fall 2011 . The survey was administered at 44 colleges and universities representing a broad assortment of types of schools and representing all major regions of the country. At each school, the survey was administered to either all students or a random sample of students, and more than 27,000 students participated in the survey. Students in the ACHA-NCHA survey were asked, "Within the last 12 months, have you been in a relationship (meaning an intimate/coupled/partnered relationship) that was emotionally abusive?" The results are given in Table 2.12 . (a) What percent of all respondents have been in an emotionally abusive relationship? (b) What percent of the people who have been in an emotionally abusive relationship are male? (c) What percent of males have been in an emotionally abusive relationship? (d) What percent of females have been in an emotionally abusive relationship? Table 2.12 Have you been in an emotionally abusive relationship? $$\begin{array}{l|rr|r} \hline & \text { Male } & \text { Female } & \text { Total } \\ \hline \text { No } & 8352 & 16,276 & 24,628 \\ \text { Yes } & 593 & 2034 & 2627 \\ \hline \text { Total } & 8945 & 18,310 & 27,255 \\ \hline\end{array}$$

Use data on college students collected from the American College Health Association-National College Health Assessment survey \(^{18}\) conducted in Fall 2011 . The survey was administered at 44 colleges and universities representing a broad assortment of types of schools and representing all major regions of the country. At each school, the survey was administered to either all students or a random sample of students, and more than 27,000 students participated in the survey. Binge Drinking Students in the ACHANCHA survey were asked, "Within the last two weeks, how many times have you had five or more drinks of alcohol at a sitting?" The results are given in Table \(2.13 .\) Table 2.13 In the last two weeks, how many times have you had five or more drinks of alcohol? $$\begin{array}{l|rr|r}\hline & \text { Male } & \text { Female } & \text { Total } \\\\\hline 0 & 5402 & 13,310 & 18,712 \\\1-2 & 2147 & 3678 & 5825 \\\3-4 & 912 & 966 & 1878 \\\5+ & 495 & 358 & 853 \\\\\hline \text { Total } & 8956 & 18,312 & 27,268 \\\\\hline\end{array}$$ (a) What percent of all respondents answered zero? (b) Of the students who answered five or more days, what percent are male? (c) What percent of males report having five or more drinks at a sitting on three or more days in the last two weeks? (d) What percent of females report having five or more drinks at a sitting on three or more days in the last two weeks?

Draw any dotplot to show a dataset that is Clearly skewed to the left.

For each set of data (a) Find the mean \(\bar{x}\). (b) Find the median \(m\). (c) Indicate whether there appear to be any outliers. If so, what are they? $$ \begin{array}{llllllll} 15, & 22, & 12, & 28, & 58, & 18, & 25, & 18 \end{array} $$

For each set of data (a) Find the mean \(\bar{x}\). (b) Find the median \(m\). (c) Indicate whether there appear to be any outliers. If so, what are they? $$ \begin{array}{l} 110, \quad 112, \quad 118, \quad 119, \quad 122, \quad 125, \quad 129, \\ 135, \quad 138, \quad 140 \end{array} $$

Give the correct notation for the mean. The average number of text messages sent in a day was 67 , in a sample of US smartphone users ages \(18-24\), according to a survey conducted by Experian. \(^{26}\)

Give the correct notation for the mean. The average number of television sets owned per household for all households in the US is 2.6 .

Arsenic in Toenails Arsenic is toxic to humans, and people can be exposed to it through contaminated drinking water, food, dust, and soil. Scientists have devised an interesting new way to measure a person's level of arsenic poisoning: by examining toenail clippings. In a recent study, \(, 9\) scientists measured the level of arsenic (in \(\mathrm{mg} / \mathrm{kg}\) ) in toenail clippings of eight people who lived near a former arsenic mine in Great Britain. The following levels were recorded: \(\begin{array}{llllll}0.8 & 1.9 & 2.7 & 3.4 & 3.9 & 7.1\end{array}\) \(\begin{array}{ll}11.9 & 26.0\end{array}\) (a) Do you expect the mean or the median of these toenail arsenic levels to be larger? Why? (b) Calculate the mean and the median. 2.62 Fiber in the Diet The number of grams of fiber eaten in one day for a sample of ten people are \(\begin{array}{ll}10 & 11\end{array}\) \(11 \quad 14\) \(\begin{array}{llllll}15 & 17 & 21 & 24 & 28 & 115\end{array}\) (a) Find the mean and the median for these data. (b) The value of 115 appears to be an obvious outlier. Compute the mean and the median for the nine numbers with the outlier excluded. (c) Comment on the effect of the outlier on the mean and on the median.

Fiber in the Diet The number of grams of fiber eaten in one day for a sample of ten people are \(\begin{array}{ll}10 & 11\end{array}\) \(\begin{array}{ll}11 & 14\end{array}\) \(\begin{array}{llllll}15 & 17 & 21 & 24 & 28 & 115\end{array}\) (a) Find the mean and the median for these data. (b) The value of 115 appears to be an obvious outlier. Compute the mean and the median for the nine numbers with the outlier excluded. (c) Comment on the effect of the outlier on the mean and on the median.

Online Cat Videos In Exercise 1.59 on page 28 , we introduced a study looking at the effect of watching cat videos on mood and energy. The authors asked participants how many cats they currently own and report 2.39 as the measure of center for this right-skewed distribution. (a) Is this measure of center the mean number of cats or the median number of cats? (Hint: Think about how the two numbers are calculated.) (b) Would we expect the mean number of cats to be greater than or less than the median?