/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 30 O The technical report "Ozone Se... [FREE SOLUTION] | 91Ó°ÊÓ

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O 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: \(\begin{array}{rrrrrrrrrrr}76 & 22 & 40 & 7 & 30 & 5 & 6 & 136 & 72 & 33 & 0 \\\ 89 & 136 & 39 & 92 & 40 & 13 & 27 & 1 & 63 & 33 & 60 \\ 27 & 16 & 63 & 32 & 20 & 2 & 15 & 36 & 19 & 39 & 130 \\ 40 & 4 & 85 & 38 & 7 & 68 & 151 & 32 & 34 & 0 & 6 \\ 43 & 89 & 34 & 0 & & & & & & & \end{array}\) Use these data to construct a boxplot that shows outliers. Write a few sentences describing the important characteristics of the boxplot.

Short Answer

Expert verified
The detailed answer would depend on the specific calculation results. In general, the boxplot would show the range, quartiles and potential outliers from the nitrous oxide emissions data. The analysis would describe these features and what they indicate about the data distribution.

Step by step solution

01

Organize Data

First, sort the given data in increasing order. This will make it easier to identify the minimum, maximum, and median values, as well as the first and third quartiles.
02

Calculate Median

The median is the middle value when the data is arranged in numerical order. If the data set contains an even number, the median is calculated as the average of the two middle values.
03

Determine Quartiles

The first quartile (Q1) is the median of the lower half of the data (not including the median if the number of data points is odd), and the third quartile (Q3) is the median of the upper half of the data. Calculate these values.
04

Interquartile Range (IQR)

The IQR is the range within which the middle 50% of values fall. It is calculated as Q3 - Q1.
05

Identify Outliers

Any data point that lies below Q1-1.5*IQR or above Q3+1.5*IQR is considered an outlier. Isolate these values.
06

Construct Boxplot

Finally, create a box with ends at Q1 and Q3. Draw a line inside the box at the median. Then draw lines (whiskers) from the box indicating the range of the data within 1.5*IQR. Indicate the outliers with individual dots.
07

Analyze and Describe

Analyze the boxplot to observe the range of the data, skewness and the outliers. Write a few sentences describing the key characteristics of the boxplot, including the spread and the location of outliers.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Nitrous Oxide Emissions Data
Understanding nitrous oxide emissions data is critical in addressing environmental concerns such as air pollution and climate change. In the context of the exercise, we're given a data set that represents the emissions in thousands of tons from 48 continental U.S. states. This type of data is essential in studying the distribution and intensity of emissions across different regions.

To provide insights, statistical tools like boxplots are used. In our case, constructing a boxplot helps visualize the emissions' data distribution, identify the central tendency, spread, and detect any outliers that may suggest anomalies or special causes such as stricter environmental regulations or higher industrial activity in certain states.
Statistical Data Organization
Before diving into complex analysis, organizing the statistical data is a fundamental first step. It's like tidying up your room so you can easily find your belongings. Similarly, by arranging the nitrous oxide emissions data in increasing order, we set the stage for efficient computation of key statistical measures.

Organizing data allows us to spot trends, clusters, and outliers more readily. The ordered list forms the basis for calculating other statistics, like the median and quartiles, and thus is a precursor to constructing our boxplot. Organization can be as simple as listing values from smallest to largest, but in large data sets, software tools can be invaluable for quick sorting and visualization.
Interquartile Range
At the heart of any boxplot is the interquartile range (IQR), which is the stretch of the data from the first quartile (Q1) to the third quartile (Q3). Think of the IQR as the 'middle ground' of your data where the majority reside. It provides a measure of variability and helps in understanding how data is spread around the median.

The calculation of IQR as Q3 minus Q1 is a way of quantifying the range of the central 50% of the data. In educational terms, if grades in a class were put into a boxplot, the IQR would show the range between the 25th and 75th percentile of the students' grades – indicating where most students' performance lies without being swayed by extreme performers.
Outlier Identification
Have you ever played a game where one player was either way better or not quite on par with the other players? In statistics, we call these players outliers. They're the data points that stand out from the rest of the data set because they're unusually high or low.

In boxplot construction, outliers can dramatically affect our view of the data's trend. They're typically identified based on the IQR; any data point more than 1.5 times the IQR above the third quartile or below the first quartile is labeled an outlier. These are important to note because they might represent extreme cases or errors in data collection and can provide valuable insights into the dataset.
Descriptive Statistics
Imagine if you had to tell someone about your favorite book but could only use a handful of numbers – that's the idea of descriptive statistics. This aspect of statistics provides a summary of data using numbers like the median, range, and standard deviation, and tools like graphs and boxplots.

With descriptive statistics, we gain a quick and simple understanding of data. For instance, the boxplot we construct from the nitrous oxide emissions data offers a snapshot of the data's distribution, showing us at a glance where most values fall (the box itself) and how varied they are (the whiskers and outliers). It's a concise summary that allows scientists and policymakers to make informed decisions without getting lost in the mass of numbers.

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Most popular questions from this chapter

\(\nabla\) 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 that 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 \(57 \mathrm{mph} ?\)

O The article "Comparing the Costs of Major Hotel Franchises" (Real Estate Review [1992]: 46-51) gave the following data on franchise cost as a percentage of total room revenue for chains of three different types: \(\begin{array}{llllllll}\text { Budget } & 2.7 & 2.8 & 3.8 & 3.8 & 4.0 & 4.1 & 5.5 \\ & 5.9 & 6.7 & 7.0 & 7.2 & 7.2 & 7.5 & 7.5 \\ & 7.7 & 7.9 & 7.9 & 8.1 & 8.2 & 8.5 & \\ \text { Midrange } & 1.5 & 4.0 & 6.6 & 6.7 & 7.0 & 7.2 & 7.2 \\\ & 7.4 & 7.8 & 8.0 & 8.1 & 8.3 & 8.6 & 9.0 \\ \text { First-class } & 1.8 & 5.8 & 6.0 & 6.6 & 6.6 & 6.6 & 7.1 \\ & 7.2 & 7.5 & 7.6 & 7.6 & 7.8 & 7.8 & 8.2 \\ & 9.6 & & & & & & \end{array}\) Construct a boxplot for each type of hotel, and comment on interesting features, similarities, and differences.

Suppose that the distribution of scores on an exam is closely described by a normal curve with mean 100 . The 1 6th percentile of this distribution is 80 . a. What is the 84 th percentile? b. What is the approximate value of the standard deviation of exam scores? c. What \(z\) score is associated with an exam score of 90 ? d. What percentile corresponds to an exam score of 140 ? e. Do you think there were many scores below 40 ? Explain.

The Highway Loss Data Institute reported the following repair costs resulting from crash tests conducted in October 2002 . The given data are for a 5 -mph crash into a flat surface for both a sample of 10 moderately priced midsize cars and a sample of 14 inexpensive midsize cars. \(\begin{array}{lrrrrr}\text { Moderately Priced } & 296 & 0 & 1085 & 148 & 1065 \\ \text { Midsize Cars } & 0 & 0 & 341 & 184 & 370 \\ \text { Inexpensive } & 513 & 719 & 364 & 295 & 305 \\ \text { Midsize Cars } & 335 & 353 & 156 & 209 & 288 \\ & 0 & 0 & 397 & 243 & \end{array}\) a. Compute the standard deviation and the interquartile range for the repair cost of the moderately priced midsize cars. b. Compute the standard deviation and the interquartile range for the repair cost of the inexpensive midsize cars. c. Is there more variability in the repair cost for the moderately priced cars or for the inexpensive midsize cars? Justify your choice. d. Compute the mean repair cost for each of the two types of cars. e. Write a few sentences comparing repair cost for moderately priced and inexpensive midsize cars. Be sure to include information about both center and variability.

Suppose that 10 patients with meningitis received treatment with large doses of penicillin. Three days later, temperatures were recorded, and the treatment was considered successful if there had been a reduction in a patient's temperature. Denoting success by \(S\) and failure by \(\mathrm{F}\), the 10 observations are \(\begin{array}{llllllllll}\mathrm{S} & \mathrm{S} & \mathrm{F} & \mathrm{S} & \mathrm{S} & \mathrm{S} & \mathrm{F} & \mathrm{F} & \mathrm{S} & \mathrm{S}\end{array}\) a. What is the value of the sample proportion of successes? b. Replace each \(\mathrm{S}\) with a 1 and each \(\mathrm{F}\) with a 0 . Then calculate \(\bar{x}\) for this numerically coded sample. How does \(\bar{x}\) compare to \(p ?\) c. Suppose that it is decided to include 15 more patients in the study. How many of these would have to be S's to give \(p=.80\) for the entire sample of 25 patients?

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