170 likes | 173 Views
Learn how to describe, display, and explore statistical data using scatter plots, box plots, and histograms. Understand the overall pattern and exceptions in the data, as well as how to interpret distributions. Discover symmetric, skewed, normal, exponential, uniform, and skewed distributions.
E N D
Chapter Two Describing, Displaying, and Exploring Statistical Data 江支弘
Displaying Data 展示數據 • First step in data analysis • 電子試算表與統計圖表 • Overall pattern整體型態/趨勢v.s. Exceptions • From graph to numerical description 江支弘
Scatter plot 江支弘
Box plot 江支弘
Displaying Distributions呈現分佈 • Distribution of a variable: what values the variable takes and how often each value occurs • Histogram直方圖 • Ex8: percent of age 65 or older, by state, p150中文 江支弘
How to make a histogram直方圖的製作 • (Ex8) Step 1數據分組: divide the range of the data into classes of equal width • Step 2分組統計次數: count the # of observations in each class 江支弘
Interpreting histograms • 與長條圖不同: base scale; width of bar; • Pattern and deviations型態與偏差 • Outlier離群值: an individual observation that falls outside the overall pattern • Overall pattern of a distribution分佈的一般型態 Center and Spread中心與離度 Shape (e.g. symmetric) 江支弘
Symmetric and Skewed distributions對稱分佈與偏斜分佈 • A distribution is Symmetric if the right and left side of the histogram are approx. mirror images of each other Skewed to the right if the right side of the histogram (upper half) extends much farther out than the left side 江支弘