2

Describing Data Graphically and Numerically

The focus of this chapter is a discussion of methods for describing sets of data.

# Topics Covered:

• Basic concepts of a population and various types of sampling designs
• Classification of the types of data
• Organizing and summarizing qualitative and quantitative data
• Describing qualitative and quantitative data graphically
• Determining measures of centrality and measures of dispersion for a set of raw data
• Determining measures of centrality and measures of dispersion for grouped data
• Determining measures of relative position
• Constructing a box whisker plot and its use in data analysis
• Determining measures of association
• Using statistical packages MINITAB, JMP, and Microsoft Excel

# Learning Outcomes:

After studying this chapter, the reader will be able to

• Select an appropriate sampling design for data collection.
• Identify suitable variables in a problem and determine the level of measurement.
• Organize, summarize, present and interpret the data.
• Identify the difference between a parameter and a statistic.
• Calculate measures of the data such as mean, mode, median, variance, standard deviation, coefficient of variation, and measure of association, and interpret them.
• Identify outliers if they are present in the data.
• Apply the statistical packages MINITAB, Microsoft Excel, and JMP to analyze the large body of data.

# 2.1 Getting Started with Statistics

## 2.1.1 What Is Statistics?

The term statistics is commonly used in two ways. On the one hand, ...

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