Chapter 4: Problem 24
Give two sets of five numbers that have the same mean but different standard deviations, and give two sets of five numbers that have the same standard deviation but different means.
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Chapter 4: Problem 24
Give two sets of five numbers that have the same mean but different standard deviations, and give two sets of five numbers that have the same standard deviation but different means.
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In a study investigating the effect of car speed on accident severity, 5000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5000 accidents, the average speed was \(42 \mathrm{mph}\) and the standard deviation was 15 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal. a. Roughly what proportion of vehicle speeds were between 27 and \(57 \mathrm{mph} ?\) b. Roughly what proportion of vehicle speeds exceeded \(57 \mathrm{mph} ?\)
Because some homes have selling prices that are much higher than most, the median price is usually used to describe a "typical" home price for a given location. The three accompanying quotes are all from the San Luis Obispo Tribune, but each gives a different interpretation of the median price of a home in San Luis Obispo County. Comment on each of these statements. (Look carefully. At least one of the statements is incorrect.) a. "So we have gone from \(23 \%\) to \(27 \%\) of county residents who can afford the median priced home at \(\$ 278,380\) in SLO County. That means that half of the homes in this county cost less than \(\$ 278,380\) and half cost more." (October 11,2001\()\) b. "The county's median price rose to \(\$ 285,170\) in the fourth quarter, a \(9.6 \%\) increase from the same period a year ago, the report said. (The median represents the midpoint of a range.)" (February 13,2002 ) c. "Your median is going to creep up above \(\$ 300,000\) if there is nothing available below \(\$ 300,000\),' Walker said." (February 26, 2002)
The technical report "Ozone Season Emissions by State" (U.S. Environmental Protection Agency. 2002) gave the following nitrous oxide emissions (in thousands of tons) for the 48 states in the continental U.S. states: \(\begin{array}{rrrrrrrrrrr}76 & 22 & 40 & 7 & 30 & 5 & 6 & 136 & 72 & 33 & 0 \\\ 89 & 136 & 39 & 92 & 40 & 13 & 27 & 1 & 63 & 33 & 60 \\ 27 & 16 & 63 & 32 & 20 & 2 & 15 & 36 & 19 & 39 & 130 \\ 40 & 4 & 85 & 38 & 7 & 68 & 151 & 32 & 34 & 0 & 6\end{array}\) \(\begin{array}{rr}40 & 4 \\ 43 & 89\end{array}\) $$ 340 $$ Use these data to construct a boxplot that shows outliers. Write a few sentences describing the important characteristics of the boxplot.
The Los Angeles Times (July 17. 1995) reported that in a sample of 364 lawsuits in which punitive damages were awarded, the sample median damage award was \(\$ 50,000\), and the sample mean was \(\$ 775,000\). What does this suggest about the distribution of values in the sample?
The following data values are 2009 per capita expenditures on public libraries for each of the 50 U.S. states (from www.statemaster.com): \(\begin{array}{rrrrrrr}16.84 & 16.17 & 11.74 & 11.11 & 8.65 & 7.69 & 7.48 \\\ 7.03 & 6.20 & 6.20 & 5.95 & 5.72 & 5.61 & 5.47 \\ 5.43 & 5.33 & 4.84 & 4.63 & 4.59 & 4.58 & 3.92 \\ 3.81 & 3.75 & 3.74 & 3.67 & 3.40 & 3.35 & 3.29 \\ 3.18 & 3.16 & 2.91 & 2.78 & 2.61 & 2.58 & 2.45 \\ 2.30 & 2.19 & 2.06 & 1.78 & 1.54 & 1.31 & 1.26 \\ 1.20 & 1.19 & 1.09 & 0.70 & 0.66 & 0.54 & 0.49\end{array}\) a. Summarize this data set with a frequency distribution. Construct the corresponding histogram. b. Use the histogram in Part (a) to find approximate values of the following percentiles: i. 50 th iv. 90 th ii. \(\quad 70\) th v. 40 th iii. 10 th
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