03/05/2003 Week #2 江支弘 Chapter Two Describing, Displaying, and Exploring Statistical Data

03/05/2003 Week #2 江支弘

03/05/2003 Week #2 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

03/05/2003 Week #2 江支弘

03/05/2003 Week #2 江支弘 Scatter plot

03/05/2003 Week #2 江支弘 Box plot

03/05/2003 Week #2 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

03/05/2003 Week #2 江支弘

03/05/2003 Week #2 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

03/05/2003 Week #2 江支弘 Step 3: Draw the histogram

03/05/2003 Week #2 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)

03/05/2003 Week #2 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

03/05/2003 Week #2 江支弘

03/05/2003 Week #2 江支弘 Normal distribution

03/05/2003 Week #2 江支弘 Exponential distribution

03/05/2003 Week #2 江支弘 Uniform distribution

03/05/2003 Week #2 江支弘 Skewed distribution