/*! 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 26 Consider the following data on t... [FREE SOLUTION] | 91Ó°ÊÓ

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Consider the following data on type of health complaint \((J=\) joint swelling, \(F=\) fatigue, \(B=\) back pain, \(\mathrm{M}=\) muscle weakness, \(\mathrm{C}=\) coughing, \(\mathrm{N}=\) nose running/irritation, \(\mathbf{O}\) - other) made by tree planters. Obtain frequencies and relative frequencies for the various categories, and draw a histogram. (The data is consistent with percentages given in the article "Physiological Effects of Work Stress and Pesticide Exposure in Tree Planting by British Columbia Silviculture Workers," Ergonomics, 1993: 951-961.) \(\begin{array}{llllllllllllll}\mathrm{O} & \mathrm{O} & \mathrm{N} & \mathrm{J} & \mathrm{C} & \mathrm{F} & \mathrm{B} & \mathrm{B} & \mathrm{F} & \mathrm{O} & \mathrm{J} & \mathrm{O} & \mathrm{O} & \mathrm{M} \\ \mathrm{O} & \mathrm{F} & \mathrm{F} & \mathrm{O} & \mathrm{O} & \mathrm{N} & \mathrm{O} & \mathrm{N} & \mathrm{J} & \mathrm{F} & \mathrm{J} & \mathrm{B} & \mathrm{O} & \mathrm{C} \\ \mathrm{J} & \mathrm{O} & \mathrm{J} & \mathrm{J} & \mathrm{F} & \mathrm{N} & \mathrm{O} & \mathrm{B} & \mathrm{M} & \mathrm{O} & \mathrm{J} & \mathrm{M} & \mathrm{O} & \mathrm{B} \\ \mathrm{O} & \mathrm{F} & \mathrm{J} & \mathrm{O} & \mathrm{O} & \mathrm{B} & \mathrm{N} & \mathrm{C} & \mathrm{O} & \mathrm{O} & \mathrm{O} & \mathrm{M} & \mathrm{B} & \mathrm{F} \\\ \mathrm{J} & \mathrm{O} & \mathrm{F} & \mathrm{N} & & & & & & & & & & \end{array}\)

Short Answer

Expert verified
The Other (O) category has the highest frequency, while Muscle Weakness (M) has the lowest.

Step by step solution

01

Count the Frequency of Each Category

Count how many times each category appears in the data set. The categories are Joint Swelling (J), Fatigue (F), Back Pain (B), Muscle Weakness (M), Coughing (C), Nose Running/Irritation (N), and Other (O).
02

Calculate Total Number of Observations

Add all the frequencies together to obtain the total number of observations in the data set. This allows you to calculate the relative frequencies in the next step.
03

Calculate Relative Frequencies

Divide each category's frequency by the total number of observations to obtain the relative frequency of each category. The formula is \(\text{Relative Frequency} = \frac{\text{Frequency of a Category}}{\text{Total Number of Observations}}\).
04

Create a Histogram

Plot a histogram using the frequencies of each category. Each category will be represented on the x-axis, and the frequency of each category will be represented on the y-axis. The height of the bar corresponds to the number of observations in each category.

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Key Concepts

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

Data Visualization
Data visualization is a key technique used to present data in a graphical format, making it easier to see patterns, trends, and outliers in the data set. It transforms complex data tables into visual representations, allowing for quick interpretation. Effective data visualization helps in understanding the overall data landscape and can provide valuable insights.
For the exercise at hand, visualization revolves around the health complaints of tree planters. By visualizing this data, we can quickly identify which health complaints are most common. Not only does this aid in easier understanding, but it also allows decision-makers to prioritize issues that need attention.
  • A well-crafted visualization can summarize large volumes of data.
  • It can highlight trends or anomalies.
  • Data visualization is crucial for informed decision-making.
By employing visualization techniques like histograms, one can easily make sense of numerical data and observe its distribution across various categories.
Frequency Distribution
Frequency distribution outlines how often each data point appears within a dataset. Understanding these distributions gives insight into data patterns and variability. In our health complaints example, the frequency distribution shows how many tree planters experienced each type of complaint.
Steps to interpret a frequency distribution:
  • Each health complaint category: e.g., Joint Swelling (J), appears a certain number of times.
  • Counting these occurrences gives us the frequency for each category.
  • Summing these frequencies provides the total number of observations.
Calculating frequency distribution allows us to understand how concentrated or dispersed the data points are. This is foundational to descriptive statistics, ensuring that complex data can be easily interpreted and analyzed. By knowing how common or rare each complaint is, better health interventions can be developed.
Histogram Construction
Constructing a histogram is an effective way to visually summarize a frequency distribution. This type of bar chart displays the frequency of different categories of data. In our case, each health complaint from tree planters forms the x-axis, and the frequency of these complaints provides the y-axis values.
Steps to build a histogram involve:
  • Identifying each unique category in the data set.
  • Calculating how often each category appears (frequency).
  • Drawing bars where each bar's height reflects the category's frequency.
A histogram illustrates the data distribution, offering a quick glance at the most common complaints. This can assist researchers and policymakers in identifying which health issues need prioritizing.
Histograms are simple yet powerful; they clearly show the distribution of quantitative data and highlight important trends or gaps in the data set.

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Most popular questions from this chapter

Many people who believe they may be suffering from the flu visit emergency rooms, where they are subjected to long waits and may expose others or themselves be exposed to various diseases. The article "Drive-Through Medicine: A Novel Proposal for the Rapid Evaluation of Patients During an Influenza Pandemic" (Ann. Emerg. Med., 2010: 268-273 described an experiment to see whether patients could be evaluated while remaining in their vehicles. The following total processing times (min) for a sample of 38 individuals were read from a graph that appeared in the cited article: \(\begin{array}{llllllll}9 & 16 & 16 & 17 & 19 & 20 & 20 & 20 \\ 23 & 23 & 23 & 23 & 24 & 24 & 24 & 24 \\ 25 & 25 & 26 & 26 & 27 & 27 & 28 & 28 \\ 29 & 29 & 29 & 30 & 32 & 33 & 33 & 34 \\ 37 & 43 & 44 & 46 & 48 & 53 & & \end{array}\) a. Calculate several different measures of center and compare them. b. Are there any outliers in this sample? Any extreme outliers? c. Construct a boxplot and comment on any interesting features.

The accompanying data set consists of observations on shower-flow rate (L/min) for a sample of \(n=129\) houses in Perth, Australia ("An Application of Bayes Methodology to the Analysis of Diary Records in a Water Use Study," J. Amer. Statist. Assoc., 1987: 705-711): \(\begin{array}{rrrrrrrrrr}4.6 & 12.3 & 7.1 & 7.0 & 4.0 & 9.2 & 6.7 & 6.9 & 11.5 & 5.1 \\ 11.2 & 10.5 & 14.3 & 8.0 & 8.8 & 6.4 & 5.1 & 5.6 & 9.6 & 7.5 \\\ 7.5 & 6.2 & 5.8 & 2.3 & 3.4 & 10.4 & 9.8 & 6.6 & 3.7 & 6.4 \\ 8.3 & 6.5 & 7.6 & 9.3 & 9.2 & 7.3 & 5.0 & 6.3 & 13.8 & 6.2 \\ 5.4 & 4.8 & 7.5 & 6.0 & 6.9 & 10.8 & 7.5 & 6.6 & 5.0 & 3.3 \\ 7.6 & 3.9 & 11.9 & 2.2 & 15.0 & 7.2 & 6.1 & 15.3 & 18.9 & 7.2 \\ 5.4 & 5.5 & 4.3 & 9.0 & 12.7 & 11.3 & 7.4 & 5.0 & 3.5 & 8.2 \\ 8.4 & 7.3 & 10.3 & 11.9 & 6.0 & 5.6 & 9.5 & 9.3 & 10.4 & 9.7 \\ 5.1 & 6.7 & 10.2 & 6.2 & 8.4 & 7.0 & 4.8 & 5.6 & 10.5 & 14.6 \\ 10.8 & 15.5 & 7.5 & 6.4 & 3.4 & 5.5 & 6.6 & 5.9 & 15.0 & 9.6 \\ 7.8 & 7.0 & 6.9 & 4.1 & 3.6 & 11.9 & 3.7 & 5.7 & 6.8 & 11.3 \\ 9.3 & 9.6 & 10.4 & 9.3 & 6.9 & 9.8 & 9.1 & 10.6 & 4.5 & 6.2 \\ 8.3 & 3.2 & 4.9 & 5.0 & 6.0 & 8.2 & 6.3 & 3.8 & 6.0 & \end{array}\) a. Construct a stem-and-leaf display of the data. b. What is a typical, or representative, flow rate? c. Does the display appear to be highly concentrated or spread out? d. Does the distribution of values appear to be reasonably symmetric? If not, how would you describe the departure from symmetry? e. Would you describe any observation as being far from the rest of the data (an outlier)?

mean \(=535\) median \(=500\) mode \(=500\) sd \(=96\) minimum \(=220\) maximum \(=925\) 5 th percentile \(=400 \quad 10\) th percentile \(=430\) 90 th percentile \(=64095\) th percentile \(=720\) What can you conclude about the shape of a histogram of this data? Explain your reasoning. [Note: A relevant reference is the article "Simple Statistics for Interpreting Environmental Data," Water Pollution Contr. Fed.J., 1981: 167-175.]

Consider numerical observations \(x_{1}, \ldots, x_{n}\). It is frequently of interest to know whether the \(x_{t}\) 's are (at least approximately) symmetrically distributed about some value. If \(n\) is at least moderately large, the extent of symmetry can be assessed from a stem-and-leaf display or histogram. However, if \(n\) is not very large, such pictures are not particularly informative. Consider the following alternative. Let \(y_{1}\) denote the smallest \(x_{i}, y_{2}\) the second smallest \(x_{i}\), and so on. Then plot the following pairs as points on a twodimensional coordinate system: \(\left(y_{n}-\bar{x}, \bar{x}-y_{1}\right)\), \(\left(y_{n-1}-\bar{x}, \bar{x}-y_{2}\right),\left(y_{n-2}-\bar{x}, \bar{x}-y_{3}\right), \ldots\). There are \(n / 2\) points when \(n\) is even and \((n-1) / 2\) when \(n\) is odd. a. What does this plot look like when there is perfect symmetry in the data? What does it look like when observations stretch out more above the median than below it (a long upper tail)? b. The accompanying data on rainfall (acre-feet) from 26 seeded clouds is taken from the article "A Bayesian Analysis of a Multiplicative Treatment Effect in Weather Modification" (Technometrics, 1975: 161-166). Construct the plot and comment on the extent of symmetry or nature of departure from symmetry. \(\begin{array}{rrrrrrr}4.1 & 7.7 & 17.5 & 31.4 & 32.7 & 40.6 & 92.4 \\ 115.3 & 118.3 & 119.0 & 129.6 & 198.6 & 200.7 & 242.5 \\ 255.0 & 274.7 & 274.7 & 302.8 & 334.1 & 430.0 & 489.1 \\ 703.4 & 978.0 & 1656.0 & 1697.8 & 2745.6 & & \end{array}\)

The amount of flow through a solenoid valve in an automobile's pollution- control system is an important characteristic. An experiment was carried out to study how flow rate depended on three factors: armature length, spring load, and bobbin depth. Two different levels (low and high) of each factor were chosen, and a single observation on flow was made for each combination of levels. a. The resulting data set consisted of how many observations? b. Does this study involve sampling an existing population or a conceptual population?

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