卡方-独立检验课题.pptVIP

卡方 独立检验 目的 介绍 卡方 -独立检验 的基本概念 卡方 -独立检验与 DMAIC 路线图相结合 DMAIC流程 分析线路图 还记得这个范例吗？ 什么是 卡方 分布? 数据 假设检验 在卡方独立检验中，统计学家对大多数的变量皆假设为独立的，因此： 理论 我们来看此范例…. 我们想要知道年龄与受聘间是否独立 所以我们假设的內容如下… H0:年龄和受聘间是独立的 Ha:年龄和受聘间是不独立的 步骤#1 步骤#2 步骤#3 步骤3（接上页） 步骤 #3 （接上页） 步骤#4 步骤#5 步骤#6 步骤#7 分析线路图 用 Minitab 分析数据 用 Minitab 分析数据 数据 卡方回顾 卡方 是本周所学工具中最不具“洞察力”、且较“难以分析”的工具 但这就是我们处理计数数据时的情况！ 您的数据收集必须是随机的 注意其他隐藏因子 (X’s) Review回顾 介绍 方差 -独立性检验 的基本概念。 将方差 -独立性检验与 DMAIC 路线图相联系 选项练习 选项练习 Correct answers – Y = Hired or Not Hired Type of data = discrete X = Young or Senior Type of Data = discrete Tool to use – Chi-Square Test Unlike the Normal Distribution, which has a constant shape, the shape of the Chi-Square Distribution depends on its “degrees of freedom”. If you recall from previous discussions, degrees of freedom is related to the sample size. For the Chi-Square distribution, degrees of freedom = n –1. The test that we use is a comparison of the frequency of the observed observations to the frequency that would be expected if the null hypothesis is true. Here is our data. 193 “Senior” people were interviewed for employment – 43 were hired and 150 were not hired. 255 “Young” people were interviewed – 45 were hired and 210 were not hired. Does it appear that the probability of being hired is related to age? To determine if there is a statistical relationship between the input data (Senior and Old) and the output data (Hired and Not Hired), we first formulate our null and alternative hypotheses. As usual, we will use a P-value of 0.05 as our decision point to reject the null hypothesis. Instructor Notes: Review the contents of the slide. Discuss and elaborate, as necessary. Instructor Notes: Review the contents of the slide. Discuss and elaborate, as necessary. Instructor Notes: Review the contents of the slide. Discuss and elaborate, as necessary. Have the class total the rows and columns. The totals have already been given on slide # 7. Instructor Notes: Review the contents