/*! 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 17 The following data represent ton... [FREE SOLUTION] | 91Ó°ÊÓ

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The following data represent tonnes of wheat harvested each year (1894-1925) from Plot 19 at the Rothamsted Agricultural Experiment Stations, England. \(\begin{array}{lllllllllll}2.71 & 1.62 & 2.60 & 1.64 & 2.20 & 2.02 & 1.67 & 1.99 & 2.34 & 1.26 & 1.31 \\ 1.80 & 2.82 & 2.15 & 2.07 & 1.62 & 1.47 & 2.19 & 0.59 & 1.48 & 0.77 & 2.04 \\ 1.32 & 0.89 & 1.35 & 0.95 & 0.94 & 1.39 & 1.19 & 1.18 & 0.46 & 0.70 & \end{array}\) (a) Multiply each data value by 100 to "clear" the decimals. (b) Use the standard procedures of this section to make a frequency table and histogram with your whole-number data. Use six classes. (c) Divide class limits, class boundaries, and class midpoints by 100 to get back to your original data values.

Short Answer

Expert verified
Multiply data by 100, create a frequency table, and histogram with six classes, then divide the class limits back by 100.

Step by step solution

01

Multiply Each Data Value by 100

To clear the decimals, take each value in the given dataset and multiply it by 100. This converts the values into whole numbers. For instance, multiplying 2.71 by 100 gives us 271. Repeat this for all data points to obtain a dataset of whole numbers: 271, 162, 260, ..., 70.
02

Determine Number of Classes

According to the problem, use six classes for the frequency table and histogram. Start by determining the range, which is the difference between the maximum and minimum values of your multiplied data set. In this case, the maximum is 282 and the minimum is 46. Thus, the range is 236 (282 - 46).
03

Calculate Class Width

Divide the range by the number of classes to get the class width. Here, the range is 236 and the number of classes is 6. So, the class width is roughly 39.33, which we round up to 40 for simplicity.
04

Construct Frequency Table with Whole Numbers

Choose a lower limit for the first class (commonly a little below the minimum value) and add the class width to get each class's upper limit, ensuring no gaps between classes. For example: 40-79, 80-119, up to 240-279. List the frequency of data points falling into each interval.
05

Construct Histogram

Plot the frequency data from each class interval against each class on the X-axis. The height of the bars will represent the frequency of data points in each interval. This gives a visual representation of data distribution.
06

Divide Class Limits by 100

Divide the class limits, boundaries, and midpoints by 100 to revert to the original decimal format. For a class of 40-79, the corresponding original class would be 0.40-0.79. Perform this division for each class range in the table and histogram.

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Key Concepts

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

Understanding Frequency Distribution
Frequency distribution is a way to organize and categorize data into set intervals, called classes. This helps us understand how often different ranges of values appear in a dataset. Imagine you are organizing a closet filled with clothes of various sizes. The frequency distribution is like grouping the clothes into size categories, such as 'small', 'medium', and 'large'.

To create a frequency distribution for data like our wheat harvest, you start by determining the number of groups or classes. Then, calculate the range of the dataset, which is the difference between the largest and smallest observations. This range helps you set up the width of each class so all data points can fit into these intervals.
  • This method structures data in a meaningful way, showing at a glance how values spread across the range.
  • It's a fundamental part of statistical analysis, aiding in both simple summaries and in setting the stage for more complex data analysis.
By examining frequency distribution, one can quickly identify patterns and anomalies that might otherwise be hidden in raw data.
Exploring Data Transformation
Data transformation involves changing the format, structure, or values of data to make it easier to analyze. In statistical analysis, transforming data often involves scaling numbers so they maintain their relative relationships, but are easier to manage.

In our exercise, multiplying the wheat data by 100 serves as a simple transformation to eliminate decimals, facilitating easier calculations and creating whole numbers. It's like zooming in on a map so that details become clearer without changing the original geography.
  • Such transformations make data more usable for specific analysis techniques, such as plotting on graphs, where whole numbers are often preferred for simplicity.
  • Another common transformation is normalization, which adjusts values measured on different scales to a common scale.
After analysis, transforming data back to its original form is crucial for interpretation. We divided the class limits and boundaries back by 100 to align the results with their real-world context, ensuring any findings remain relevant and actionable.
The Art of Histogram Construction
Constructing a histogram is akin to drawing a bar chart, where each bar represents the frequency of data within a class interval. This visual representation is crucial in helping us quickly see the underlying patterns of a dataset.

To create a histogram from our frequency table:
  • Place the class intervals on the horizontal axis (X-axis). Each interval represents a range of data points.
  • On the vertical axis (Y-axis), place the frequency of occurrences within each class.
  • The height of each bar represents how many data points fall into each interval.
Histograms provide a snapshot that immediately highlights the distribution shape - whether it is symmetric, skewed, bimodal, or uniform. They can reveal trends, highlight outliers, and identify modal values (most frequent class). A well-constructed histogram not only simplifies complex datasets but also enhances communication, making it an essential tool for statisticians and data storytellers alike.

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Most popular questions from this chapter

It is costly in both time and money to go to college. Does it pay off? According to the Bureau of the Census, the answer is yes. The average annual income (in thousands of dollars) of a housebold headed by a person with the stated education level is as follows: \(16.1\) if ninth grade is the highest level achieved, \(34.3\) for high school graduates, \(48.6\) for those holding associate degrees, \(62.1\) for those with bachelor's degrees, \(71.0\) for those with master's degrees, and \(84.1\) for those with doctoral degrees. Make a bar graph showing household income for each education level.

Driving would be more pleasant if we didn't have to put up with the bad habits of other drivers. USA Today reported the results of a Valvoline Oil Company survey of 500 drivers, in which the drivers marked their complaints about other drivers. The top complaints turned out to be tailgating, marked by \(22 \%\) of the respondents; not using turn signals, marked by \(19 \% ;\) being cut off, marked by \(16 \%\); other drivers driving too slowly, marked by \(11 \% ;\) and other drivers being inconsiderate, marked by \(8 \% .\) Make a Pareto chart showing percentage of drivers listing each stated complaint. Could this information as reported be put in a circle graph? Why or why not?

A personnel office is gathering data regarding working conditions. Employees are given a list of five conditions that they might want to see improved. They are asked to select the one item that is most critical to them. Which type of graph, circle graph or Pareto chart, would be most useful for displaying the results of the survey? Why?

The U.S. Open Golf Tournament was played at Congressional Country Club, Bethesda, Maryland, with prizes ranging from \(\$ 465,000\) for first place to \(\$ 5000\). Par for the course was \(70 .\) The tournament consisted of four rounds played on different days. The scores for each round of the 32 players who placed in the money (more than \(\$ 17,000\) ) were given on a web site. For more information, visit the Brase/Brase statistics site at http://www.cengage.com/statistics/brase and find the link to golf. The scores for the first round were as follows: \(\begin{array}{lllllllllll}71 & 65 & 67 & 73 & 74 & 73 & 71 & 71 & 74 & 73 & 71 \\ 70 & 75 & 71 & 72 & 71 & 75 & 75 & 71 & 71 & 74 & 75 \\ 66 & 75 & 75 & 75 & 71 & 72 & 72 & 73 & 71 & 67 & \end{array}\) The scores for the fourth round for these players were as follows: \(\begin{array}{lllllllllll}69 & 69 & 73 & 74 & 72 & 72 & 70 & 71 & 71 & 70 & 72 \\ 73 & 73 & 72 & 71 & 71 & 71 & 69 & 70 & 71 & 72 & 73 \\ 74 & 72 & 71 & 68 & 69 & 70 & 69 & 71 & 73 & 74 & \end{array}\) (a) Make a stem-and-leaf display for the first-round scores. Use two lines per stem. (See Problem 5.) (b) Make a stem-and-leaf display for the fourth-round scores. Use two lines per stem. (c) Compare the two distributions. How do the highest scores compare? How do the lowest scores compare?

A data set with whole numbers has a low value of 10 and a high value of 120 . Find the class width and class limits for a frequency table with 5 classes.

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