结果:找到“Modern statistics”相关内容91个,排序为按回复时间降序,搜索更多相关帖子请点击“高级
A Modern Introduction to Probability and Statistics: Understanding Why and How
21 个回复 - 4679 次查看 Suitable for self studyUse real examples and real data sets that will be familiar to the audience Introduction to the bootstrap is included – this is a modern method missing in many other booksProdu ...2015-4-16 18:09 - lasgpope - 量化投资
Modern Bayesian Statistics in Clinical Research
34 个回复 - 2920 次查看 1**** 本内容被作者隐藏 ****2018-12-25 03:10 - Nicolle - winbugs及其他软件专版
Basics of Modern Mathematical Statistics
13 个回复 - 2971 次查看 This textbook provides a unified and self-contained presentation of the main approaches to and ideas of mathematical statistics. It collects the basic mathematical ideas and tools needed as a basis fo ...2015-4-16 22:18 - lasgpope - 量化投资
现代贝叶斯统计学Modern Bayesian Statistics
4 个回复 - 3438 次查看 现代贝叶斯统计学Modern Bayesian StatisticsSAMUEL KOTZ 吴喜之著中国统计出版社 2000 第一章 贝叶斯立场(D.V.Lindley) 第二章 先验分布,后验分布及贝叶斯推断第三章 常用分布第四章 可靠性问题第五章 经验贝叶斯方 ...2014-10-8 10:21 - kongjih - 计量经济学与统计软件
Modern Mathematical Statistics with Applications 2e Jay L.Devore 教材+奇数题答案
10 个回复 - 7184 次查看 教材+奇数题答案Modern Mathematical Statistics with Applications 2e Jay L. Devore ,Kenneth N Berk2018-10-30 17:55 - gold-leaf - R语言论坛
Applied Directional Statistics: Modern Methods and Case Studies
4 个回复 - 487 次查看 Applied Directional Statistics: Modern Methods and Case Studies - Christophe Lee [*]Publisher: Chapman and Hall/CRC; 1 edition (September 10, 2018) [*]Language: English [*]ISBN-10: 978113862 ...2018-12-17 23:05 - chicu - 经管书评
Modern Mathematical Statistics with Applications 答案
9 个回复 - 6321 次查看 Modern Mathematical Statistics with Applications 答案2016-2-20 07:16 - 天才小十二 - 计量经济学与统计软件
【经典教材系列】Modern Statistics for the Social and Behavioral Sciences
164 个回复 - 10934 次查看 2011年经典教材(共862页)降价出售期已过!想要随时跟踪最新降价好书,请点击头像下方“加关注”。关注成功后,查看这里即可:三步走把千本好书“一网打尽”!。 [相关阅读] 【经典教材系列】(资料汇总帖,附链 ...2015-7-21 19:44 - wwqqer - 行为经济学与实验经济学
Springer: Basics of Modern Mathematical Statistics
7 个回复 - 2171 次查看 话说论坛有几贴Basics of Modern Mathematical Statistics居然全都是solutions我也是醉了。。。 该书本尊在此。2015-1-30 19:29 - cfwsoc - 计量经济学与统计软件
Basics of Modern Mathematical Statistics
23 个回复 - 5467 次查看 **** 本内容被作者隐藏 ****2015-3-30 00:36 - hqchi - 经济金融数学专区
Basics of Modern Mathematical Statistics
7 个回复 - 1786 次查看 【作者(必填)】 [*]Wolfgang Karl Härdle, [*]Vladimir Spokoiny, [*]Vladimir Panov, [*]Weining Wang 【文题(必填)】Basics of Modern Mathematical Statistics 【年份(必填)】2014 【全文链 ...2013-11-25 17:09 - 352693585 - 求助成功区
第二版 Modern mathematical statistics with applications
16 个回复 - 3761 次查看 第二版 Modern mathematical statistics with applications 書刊名: Modern mathematical statistics with applications 作者: Jay L. Devore其他作者: Kenneth N Berk 主題: Mathematical statistics ; Statistics ...2012-10-4 10:13 - otarublue - 计量经济学与统计软件
Essentials of Modern Business Statistics with Microsoft Office Excel, 7th Ed.
13 个回复 - 3220 次查看 Essentials of Modern Business Statistics with Microsoft Office Excel, 7th Edition by David R. Anderson (Author), Dennis J. Sweeney (Author), Thomas A. Williams (Author), Jeffrey D. Camm (Author), Jam ...2021-2-21 10:46 - slowry - 金融学(理论版)
免费的Modern Applied Statistics With S(4th Ed)
14 个回复 - 4395 次查看 希望大家喜欢。2013-1-22 21:35 - tunxier - 计量经济学与统计软件
Essentials of modern business statistics
0 个回复 - 598 次查看 复制这段内容后打开百度网盘手机App,操作更方便哦 链接:https://pan.baidu.com/s/1EdJ7ttY0erwAefm_2S-nqA 提取码:p3u22020-8-14 16:28 - carol168 - 爱问频道
【学习笔记】Essentials of Modern Business Statistics (7e)
1 个回复 - 514 次查看 Essentials of Modern Business Statistics (7e)2020-7-19 16:09 - bingdianyidu - Forum
Modern Elementary Statistics 12th Edition
8 个回复 - 4476 次查看 Modern Elementary Statistics John E. Freund Benjamin M. Perles Twelfth Edition2017-4-20 14:52 - cuijin4161 - 经济金融数学专区
Intermediate_Statistics__A_Modern_Approach__3rd_edition
5 个回复 - 2947 次查看 . 2007 by Taylor & Francis Group, LLC Lawrence Erlbaum Associates is an imprint of Taylor & Francis Group, an Informa business Preface xi Chapter 1 INTRODUCTION 1 1.1 Focus and Overview of Topi ...2011-8-27 11:01 - davidhaitaopan - R语言论坛
Modern Regression Methods Wiley Series in Probability and Statistics
2 个回复 - 2046 次查看 Modern Regression Methods Wiley Series in Probability and Statistics. Applied Probability and Statistics 书的介绍见 http://www.pinggu.org/bbs/viewthread.php?tid=536497&highlight=Modern%2BRegres ...2010-10-18 14:18 - fisher163 - 计量经济学与统计软件
Modern Regression Methods (Wiley Series in Probability and Statistics)
4 个回复 - 1797 次查看 Modern Regression Methods (Wiley Series in Probability and Statistics)2010-4-4 20:33 - xiaohaha008 - 计量经济学与统计软件
[悬赏】Introduction to Modern Nonparametric Statistics by James J. Higgins
11 个回复 - 3883 次查看 [悬赏】Introduction to Modern Nonparametric Statistics by James J. Higgins 论坛币全在这里了 求这本书2014-1-17 08:38 - kgbonl - 计量经济学与统计软件
【学习笔记】求 Essential of Modern Business Statistics(7)
2 个回复 - 318 次查看 求 Essential of Modern Business Statistics(7)2019-11-13 19:51 - bingdianyidu - Forum
【学习笔记】哪位大侠有modern Bayesian statistics in clinical trial?
1 个回复 - 543 次查看 哪位大侠有modern Bayesian statistics in clinical trial?2019-12-29 17:37 - southlander - Forum
统计书籍Modern.Mathematical.Statistics.with.Applications,.Devore,.Berk,.2ed,.Spr
8 个回复 - 2790 次查看 Modern.Mathematical.Statistics.with.Applications,.Devore,.Berk,.2ed,.Springer,.20122013-7-19 12:44 - jf9904014 - SAS专版
[北美最流行]现代工业统计Modern Industrial Statistics 2nd ed._Ron Kenett
116 个回复 - 13503 次查看 2014新书现代工业统计及R等应用(第2版) Modern Industrial Statistics: with applications in R, MINITAB and JMP, 2nd Edition by Ron Kenett, Shelemyahu Zacks, Daniele Amberti 2014 | ISBN: 1118456068 | E ...2014-6-30 19:21 - saintsophia - 经济金融数学专区
[R]Modern Industrial Statistics with applications in R, MINITAB and JMP
33 个回复 - 8234 次查看 Modern Industrial Statistics ——with applications in R, MINITAB and JMP2015-8-6 19:18 - niuniuyiwan - R语言论坛
求Essentials of Modern Business Statistics with Microsoft Excel 第七版
4 个回复 - 1244 次查看 求Essentials of Modern Business Statistics with Microsoft Excel 第七版2017-8-18 23:32 - wang_mic - 悬赏大厅
Essentials of Modern Business Statistics with Microsoft Excel 5th
26 个回复 - 3323 次查看 December 2011 | English | PDF | ISBN-10: 0840062389 | 784 Page From the renowned author team that has been writing market-leading business statistics textbooks for more than 20 years, ESSENTIAL ...2018-5-15 11:20 - igs816 - Excel
Modern Business Statistics with Microsoft Excel 5th edition
12 个回复 - 3775 次查看 Modern Business Statistics with Microsoft Excel 5th edition by Anderson, Sweeney, Williams2014-10-5 08:52 - bunnychow - 会计与财务管理
(下载好书)Modern Applied Statistics with S-Plus
13 个回复 - 5614 次查看 W. N. Venables and B. D. Ripley的一本很不错的书2011-3-5 19:34 - hitmz - R语言论坛
ModernAppliedStatisticswithS(4ed);数据可视化及基础分析方法;R的学习文档
1 个回复 - 1044 次查看 Modern Applied Statistics with S(4ed);数据可视化及基础分析方法; R的学习文档(是关于R.Cookbook的概要文档,详细、思路清晰、分类明晰、重点突出,推荐)2018-7-12 14:26 - catherine192 - 金融学(理论版)
Modern Engineering Statistics】
7 个回复 - 2355 次查看 第一次发帖,,刚才搜索了一下没有这本书,所以。。。 *名称: Modern Engineering Statistics THOMAS P. RYAN *大小:609页 *格式:PDF *目录: Contents Preface xvii 1. Methods of Collecting and ...2010-1-1 16:15 - foggycanyon - 计量经济学与统计软件
Essentials of Modern Business Statistics with Microsoft Office Excel 6th edition
1 个回复 - 1466 次查看 【作者(必填)】Anderson, Sweeney, and Williams 【文题(必填)】Essentials of Modern Business Statistics with Microsoft Office Excel 【年份(必填)】6th edition2018-6-26 22:01 - 多多11022 - 文献求助专区
Introduction to Modern Nonparametric Statistics by Higgins 部分解答
11 个回复 - 11374 次查看 淺顯易懂的無母數教科書祝大家學習愉快!2014-6-30 18:28 - ccwang03 - 计量经济学与统计软件
求Essentials of Modern Business Statistics with Microsoft Excel
7 个回复 - 1801 次查看 Essentials of Modern Business Statistics with Microsoft Excel [Hardcover] David R. Anderson (Author), Dennis J. Sweeney (Author), Thomas A. Williams (Author)2014-2-14 15:49 - kingvern - 求助成功区
Modern Applied Statistics with S-[W.N. Venables, B.D. Ripley]
4 个回复 - 1825 次查看 书籍信息: 标题: Modern Applied Statistics with S 语言: English 格式: pdf 大小: 2.6M 页数: 505 年份: 2002 作者: W.N. Venables, B.D. Ripley 版次: 4th 系列: Statistics and Computing 出版社 ...2017-11-22 17:18 - 瘦瘦三国 - 数据分析与数据挖掘
Modern Directional Statistics
34 个回复 - 1792 次查看 2017 | ISBN: 1498706649 | English | 192 pages | PDF | 10 MB Modern Directional Statistics collects important advances in methodology and theory for directional statistics over the last two decades. ...2017-8-19 22:35 - igs816 - 经管书评
Need the ebook: Introduction to Modern Nonparametric Statistics by Higgins
11 个回复 - 5373 次查看 Does anyone have this ebook? I'm sorry I could not type in Chinese at work right now. But I would like to pay reasonable amount of lun tan bi to buy this book. Thanx2010-4-9 00:17 - sigrid28 - 计量经济学与统计软件
求书Introduction to Modern Nonparametric Statistics, James J. Higgins, 2004
4 个回复 - 3788 次查看 如题,急需,悬赏一千,谢谢2010-8-28 01:29 - tlola - 计量经济学与统计软件
【数据分析电子书免费下载】Modern Applied Statistics With S 第四版 pdf_下载_mobi
0 个回复 - 1525 次查看 【数据分析电子书免费下载】Modern Applied Statistics With S 第四版 pdf_下载_mobi 内容描述: S is a powerful environment for the statistical and graphical analysis of data. It provides the ...2017-1-2 17:32 - 数据分析闯天下 - 数据分析与数据挖掘
【数据分析电子书免费下载】Modern Applied Statistics With S 第四版pdf_下载_mobi
0 个回复 - 980 次查看 【数据分析电子书免费下载】Modern Applied Statistics With S 第四版pdf_下载_mobi 内容描述: S is a powerful environment for the statistical and graphical analysis of data. It provides the t ...2016-12-30 16:52 - 数据分析闯天下 - 数据分析师(CDA)专版
South Western出版社Modern Business Statistics with Microsoft Office Excel,4e英文
3 个回复 - 1485 次查看 South-Western Cengage Learning出版社, 作者David R. Anderson, Dennis J. Sweeney, Thomas A. WillamsModern Business Statistics with Microsoft Office Excel,4e第四版 英文原版PDF2016-6-20 08:46 - CarolPan9611 - 金融学(理论版)
求助内容“求Modern Business Statistics with Microsoft Excel [第5版】"
9 个回复 - 2341 次查看Modern Business Statistics with Microsoft Excel [第5版】,亲,一定要是第5版哦 具体要求: 1、必须是第5版 2、以英文为主,若有中文更好,每版各500金币 3、若只有英文版本者,最早提供者支付1000金币2014-8-18 09:42 - happyboy62 - 求助成功区
Modern Applied Statistics With S
71 个回复 - 26235 次查看 Book : Modern Applied Statistics with S. 4th edition. Format : pdf. 495 pages. Size : 2.97MB. Publisher : Springer Content: 1 Introduction 2 Data Manipulation 3 The S Language 4 Graphics 5 U ...2006-11-25 16:26 - yiyo900 - R语言论坛
Classic Topics on the History of Modern Mathematical Statistics
33 个回复 - 4299 次查看 Classic Topics on the History of Modern Mathematical Statistics: From Laplace to More Recent Times by Prakash Gorroochurn 2016 | ISBN-10: 1119127920 | 776 pages | PDF | 31 MB This book pr ...2016-5-5 12:08 - tigerwolf - 管理信息系统
Modernizing Federal Economic Statistics
1 个回复 - 607 次查看 【作者(必填)】Bostic, William G.; Jarmin, Ron S.; Moyer, Brian 【文题(必填)】Modernizing Federal Economic Statistics 【年份(必填)】2016 【全文链接或数据库名称(选填)】http://www.ingentaconnect ...2016-9-7 16:32 - qianhaoqi - 求助成功区
Gail 的 Modern Issues And Methods In Biostatistics
0 个回复 - 823 次查看 Gail 的 Modern Issues And Methods In Biostatistics2016-8-12 03:03 - leonliu123 - 新手入门区
Modern Applied Statistics with S-Plus》:英文版的教材跟学习笔记
16 个回复 - 5289 次查看 好东西,大家分享!2009-11-15 14:12 - zxm403 - R语言论坛
Modern Issues and Methods in Biostatistics.df
1 个回复 - 1192 次查看 Modern Issues and Methods in Biostatistics. 最近10年生统领域的热门话题总结归纳,很不错的生统书籍2016-7-11 10:20 - voiceofboston - 计量经济学与统计软件
Modern Applied Statistics with S, 4th Ed
4 个回复 - 1200 次查看 Modern Applied Statistics with S, 4th Ed2015-5-18 13:59 - mlhhdu - R语言论坛
Basics of Modern Mathematical Statistics-Exercises and Solutions Springer 2014
33 个回复 - 5080 次查看 Basics of Modern Mathematical Statistics: Exercises and Solutions (Springer Texts in Statistics) Wolfgang Karl Härdle (Author), Vladimir Spokoiny (Author), Vladimir Panov (Author), Weining ...2014-7-26 05:39 - Nicolle - HLM专版
求Basics of modern parametric statistics
2 个回复 - 748 次查看 求 Spokoiny, V., & Dickhaus, T. (2014). Basics of modern parametric statistics. Berlin: Springer.2016-4-13 00:46 - jcx350 - 计量经济学与统计软件
modern business statistics 商业统计 双语
2 个回复 - 1333 次查看 spiceland modern business statistics 商业统计 双语2016-1-5 00:33 - zyxxyz4453 - 新手入门区
Modern Mathematical Statistics with Applications
3 个回复 - 2425 次查看 "Modern Mathematical Statistics with Applications" by Jay L. Devore, Kenneth N. Berk Duхburу, Thоmsоn Brооks/Cоle Higher Education | 2007 | ISBN: 0534404731 | 849 pages | PDF | 6 MB ...2012-7-4 00:20 - eurwalt - 金融工程(数量金融)与金融衍生品
Modern Applied Statistics with S-PLUS的一些补充
18 个回复 - 5493 次查看 本来不打算开新贴,但是这个Complements确实非常有用,提醒大家注意一下。希望大家能和原贴配合起来学习。 谢谢原贴贴主yiyo900,那本书确实不错。 另:应yiyo900兄所托特附上本书的Exercises and Selected Answ ...2007-3-11 21:38 - peterf - R语言论坛
Modern business Statistics第5版的datasets如何下载
0 个回复 - 595 次查看 请问哪位大侠知道Modern business Statistics第5版的datasets如何下载?好像是要有Access Code才行,但有人说在书里面就有教怎么下载,我在书里却没找到方法。急求大佬们解答,谢谢啦!!!2015-8-31 07:00 - iamcoldwind - 灌水吧
Modern Business Statistics with Microsoft Excel
1 个回复 - 1132 次查看 Modern Business Statistics with Microsoft Excel (with Printed Access Card) [Hardcover] David R. Anderson (Author), Dennis J. Sweeney (Author), Thomas A. Williams (Author)2014-2-14 12:03 - kingvern - 悬赏大厅
Arthur L. Bowley: A Pioneer In Modern Statistics And Economics
12 个回复 - 246 次查看 "Arthur L. Bowley": A Pioneer In Modern Statistics And Economics by Kotz Samuel Et Al 2011 | ISBN-10: 9812835504 | 544 pages | PDF | 4 MB Arthur Lyon Bowley, the founding father of modern statis ...2014-8-6 13:50 - tigerwolf - 宏观经济学
Basics of Modern Mathematical Statistics Exercises and Solutions
0 个回复 - 1028 次查看 Wolfgang Karl Härdle  Vladimir Spokoiny Vladimir Panov  Weining Wang Basics of Modern Mathematical Statistics Exercises and Solutions2014-10-16 19:46 - li_mao - 计量经济学与统计软件
Springer05 - A Modern Introduction to Probability and Statistics
2 个回复 - 2841 次查看 A Modern Introduction to Probability and StatisticsUnderstanding Why and HowPublisher: Springer 2005Authors: F.M. Dekking, C. Kraaikamp, H.P. Lopuhaa, L.E. MeesterContents1 Why probability and statist ...2008-10-7 02:30 - lj1001 - 计量经济学与统计软件
Basics of Modern Mathematical Statistics: Exercises and Solutions
90 个回复 - 11408 次查看 The complexity of today’s statistical data calls for modern mathematical tools. Many fields of science make use of mathematical statistics and require continuous updating on statistical technologies ...2014-7-20 03:52 - 大家开心 - 计量经济学与统计软件
求:Modern Industrial Statistics
1 个回复 - 1166 次查看 Modern Industrial Statistics: The Design and Control of Quality and Reliability 作者:Kenett, Ron2013-4-26 14:48 - 帅到被追杀 - 悬赏大厅
求Essentials of Modern Business Statistics 第五版
5 个回复 - 1485 次查看 求Essentials of Modern Business Statistics ISBN-13: 978-0840062383 需要第五版PDF或者能打印出来的版本都行 作者是 Anderson, David R - Sweeney, Dennis J - Williams, Thomas 哪位有资源共享一下,谢谢 ...2014-1-15 05:47 - frozenzxz - 悬赏大厅
下载《Modern Applied Statistics with S》第四版所有R代码
7 个回复 - 2528 次查看 搜了一下,好像没有重复。R本自身是免费开源软件,呼吁大家免费共享R有关的资料。2010-12-2 08:44 - dengyishuo - R语言论坛
Modern Applied Statistics with S-Plus
12 个回复 - 8111 次查看 [此贴子已经被作者于2007-3-29 21:12:06编辑过]2007-3-29 20:05 - klnmail - R语言论坛
Modern Applied Statistics with S-Plus
11 个回复 - 4154 次查看 Contents1 Starting R 41.1 Installing R . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.2 Basic R Commands . . . . . . . . . . . . . . . . . . . . . . . 41.3 An Example of an R Session . . . ...2007-5-27 08:16 - shium - R语言论坛
[原创]Springer ebook5-A Modern Introduction to Probability and Statistics
12 个回复 - 5390 次查看 <H2>A Modern Introduction to Probability and Statistics</H2> <DIV>Understanding Why and How<br>Series: <a href="http://www.springer.com/west/home/statistics?SGWID=4-10128-69-17362 ...2007-3-2 15:20 - ccpoo - 计量经济学与统计软件
Exercises for Modern Applied Statistics with S (4th ed)
5 个回复 - 4050 次查看 Exercises for Modern Applied Statistics with S (4th ed) [此贴子已经被作者于2007-10-22 11:24:44编辑过]2007-10-22 09:56 - ktpoon - R语言论坛
Modern Applied Statistics With S
2 个回复 - 3416 次查看 [此贴子已经被作者于2007-3-31 20:34:13编辑过]2007-3-29 20:58 - klnmail - R语言论坛
Modern Applied Statistics With S-Springer-Verlag
1 个回复 - 2401 次查看 Modern Applied Statistics With S-Springer-Verlag [此贴子已经被作者于2007-1-19 4:28:22编辑过]2007-1-18 13:55 - gullnk - R语言论坛
Modern Applied Statistics With S(4th edition)
5 个回复 - 4784 次查看 by:W. N.VenablesandB.D.Ripley Springe Final15March2002 一本比较全面的S语言的教材,概述了S语言的基本功能与基本应用函数(详见目录),PDF版本。英文。 目录: 1、简介 2、数据管理 3、S语言 4、绘图 ...2006-11-6 01:21 - Aoisorani - 计量经济学与统计软件
Statistics - Springer-Verlag - Modern Applied Statistics With S
2 个回复 - 2138 次查看 因为要购买论坛中其他的书 [/UseMoney] 抱歉,那个东西要很多钱,所以再卖一本,帮帮忙 Kannan-Introduction to stochastic processes,是DJVU格式的 [此贴子已经被作者于2005-9-28 22:06:02编辑过]2005-9-28 21:52 - iamaminer - 计量经济学与统计软件
[下载]Modern Applied Statistics With S (4th ed) with some other complements
4 个回复 - 1742 次查看 共有三个资料1 英文原版书2 原书作者对书的补充3 一位老师基于此书的notes原书目录ContentsPreface1. Introduction1.1 Failure Time Data, 11.2 Failure Time Distributions, 61.3 Time Origins, Censoring, and Tru ...2008-12-25 13:10 - herline - 计量经济学与统计软件
[下载]Statistics at Square Two Understanding modern statistical by M. J. Campbell
0 个回复 - 2583 次查看 Statistics at Square Two Understanding modern statistical by M. J. Campbell Paperback: 133 pages Publisher: Bmj Publishing Group; 1st edition (August 15, 2001) ISBN: 0727913948 Product Dimensio ...2005-3-4 06:08 - leijx - 计量经济学与统计软件
名书:统计在R中的应用,Venables_Ripley_Modern_Applied_Statistics_with_S_(4ed)
0 个回复 - 1339 次查看 这本书对学习R,和统计应用,很有帮助,有500多页,详细介绍了如下: Preface v Typographical Conventions xi 1 Introduction 1 1.1 A Quick Overview of S . . . . . . . . . . . . . . . . . . . . . . . ...2011-9-15 05:41 - xyy2006 - 计量经济学与统计软件
Modern Applied Statistics With S
5 个回复 - 1515 次查看 Modern Applied Statistics With S 4 edition2010-3-11 15:39 - renda_shitou - R语言论坛
modern applied statistics with s-plus下载
2 个回复 - 2018 次查看 哪位大侠有这本书的下载哇 拜谢!!!2009-9-7 23:25 - GreenmyDay - R语言论坛
[分享]Modern Applied Statistics With S
4 个回复 - 3491 次查看 一本S 语言的书,偶尔在硬盘的角落里发现,都忘了什么时候下载的啦希望对大家有帮助传到G宝盘了http://wangwangba.gbaopan.com/files/8a4b6eec13ad46d69756264452e24d8f.gbp2007-8-21 23:59 - zkiller - R语言论坛