Stock Market Prices Do Not Follow Random Walks: Evidence from a Simple Specification Test Andrew W. Lo A. Craig MacKinlay University of Pennsylvania In this article we test the random walk hypothesis for weekly stock market returns by comparing variance estimators derived from data sampled at different frequencies. The random walk model is strongly rejected for the entire sample period (19621985) and for all subperiod for a variety of aggregate returns indexes and size-sorted portofolios. Although
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BURNS Disasters Once a disaster is declared‚ then the disaster is classified according to the level of response needed to cope with the situation. This incident is declared a Level I disaster according to the local community disaster plan. [pic][pic][pic] 1. Which action is included when a Level I disaster is declared? All local hospitals prepare to receive casualties. Feedback: Classification as a Level I disaster indicates that local emergency response personnel and organizations can
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Differences Understand Generational Differences For the first time in history‚ four generations are working side by side. Different values‚ experiences‚ styles‚ and activities create misunderstandings and frustrations By the year 2014‚ 70 million Baby Boomer (including many teachers and school leaders) will entire retirement in large numbers Generation X‚ a generation with different sensibilities and priorities than Boomers‚ will assume positions of leadership in schools
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Types of Sampling In applications: Probability Sampling: Simple Random Sampling‚ Stratified Random Sampling‚ Multi-Stage Sampling * What is each and how is it done? * How do we decide which to use? * How do we analyze the results differently depending on the type of sampling? Non-probability Sampling: Why don’t we use non-probability sampling schemes? Two reasons: * We can’t use the mathematics of probability to analyze the results. * In general‚ we can’t count on a non-probability
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Depending on how a sample is drawn‚ it may be a random sample or a nonrandom sample. A random sample is a sample drawn in such a way that each member of the population has some chance of being selected in the sample. In a nonrandom sample‚ some members of the population may not have any chance of being selected in the sample. Suppose we have a list of 100 students and we want to select 10 of them. If we write the names of all 100 students on pieces of paper‚ put them in a hat‚ mix them‚ and then
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the selection of an unbiased or random subset of individual observations within a population of individuals intended to yield some knowledge about the population of concern‚ especially for making predictions based on the statistical inference (Ader‚ Mellenberg & Hand: 2008). There are quite a number of sampling methods that can be employed in research and these include simple random sampling‚ systematic sampling‚ stratified sampling‚ cluster sampling‚ matched random sampling‚ quota sampling‚ convenience
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There are many ways to select a random sample. Four of them are discussed below: Simple Random Sampling: In this sampling technique‚ each sample of the same size has the same probability of being selected. Such a sample is called a simple random sample. One way to select a simple random sample is by a lottery or drawing. For example‚ if we need to select 5 students from a class of 50‚ we write each of the 50 names on a separate piece of paper. Then‚ we place all 50 names in a hat and mix them thoroughly
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a sample that is similar to the population on all characteristics. Two-stage random sampling A process in which clusters are first randomly selected and then individuals are selected from each cluster. Stratified random sampling The process of selecting a sample in such a way that identified subgroups in the population are represented in the sample in the same proportion as they exist in the population. Random sampling Methods designed to select a representative sample by using chance selection
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Chapter 19 The Party System * Secession: The act of withdrawing formally from membership; South Withdrew from the Union starting civil war. * S. Carolina seceded first * Condfederate States of America : New Nation made of the Southern states ; formed in Montgomery‚Alabama * Occurred when President Lincoln took office * Federal government had no power to stop the states from ceding from the Union * Seceding states had no military power to seize Fort Sumter nor
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报章报道: 国家环境局发言人透露， 违例者均为初犯， 罚款额为200元， 重犯可罚高达1000元。 除此， 放置在及新增禁烟区内的垃圾桶将移走， 換成不设烟灰缸的桥‚ 垃圾捅。 读了这则新闻‚ 我不禁感到欣慰‚ 赞成违例者会被惩罚的行为‚ 相信新加坡公民也会点头咂嘴。 国家随着新加坡烟民逐年增加‚ 本地公共场所的禁烟范围正式扩大近三个月来， 共有超过500名烟客在新禁烟令下违例吸烟而遭罚款。 他们多数是在有盖走廊， 住宅区公共空间， 及有盖行人天桥等处被稽査人员逮个正着。 原因: • 环境局数据显示， 本地去年全年共有4050起烟客违例吸烟铵罚款案例 • 烟客喜欢聚集在有烟灰缸的垃圾桶抽烟，所以这些垃圾桶都被搬离到巴士站五公尺远的地方 • 当局希望通过店员和烟客的接触，把信息传达出去‚ 让禁烟信息在社区内的渗透度更广 • 让违例者遵守新禁烟令的条规 • 提高公众对新增禁烟区的认识， 环境局的义工至今已展开超过950次的社区巡逻， 向各个社区内桶的烟客和居民说明新禁烟条例 • 不要伤害到非吸烟者‚ 减少二手烟的问题 后果: • 我国约有36万烟民
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