商业模型英文教程Module2DisplayingandSummarizingData.ppt

Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Example: Facebook Friends Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Histogram Column chart representing a frequency distribution Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Excel Tool: Histogram Excel Menu >Tools > Data Analysis > Histogram Specify range of data Define and specify bin range (recommended) Select output options (always check Chart Output Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Examples from Facebook Survey Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Good Practice Guidelines Cell intervals should be of equal width. Choose the width using the formula (largest value – smallest value)/number of cells but round to reasonable values (e.g., 97 to 100) Choose somewhere between 5 to 15 cells to provide a useful picture of the data Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Excel Frequency Function Define bins Select a range of cells adjacent to the bin range (if continuous data, add one empty cell below this range as an overflow cell) Enter the formula =FREQUENCY(range of data, range of bins) and press Ctrl-Shift-Enter simultaneously. Construct a histogram using the Chart Wizard for a column chart. Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Skewness Coefficient of skewness (CS) -0.5 < CS < 0.5 indicates relative symmetry Relatively Symmetric Positively skewed Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Kurtosis Refers to the peakedness or flatness of a distribution. Coefficient of kurtosis (CK) CK < 3: more flat with wide degree of dispersion CK >3 more peaked with less dispersion The higher the kurtosis, the more area in the tails of the distribution Copyright ? 2010 Pearson Education, Inc. ?Publishing as Prentice Hall 2-* Data Profiles (Frac