矩偏度系数

 
在统计学中,定义非组变量和组变量的 k 阶样本中心矩分别为
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当分布对称时,奇数阶中心矩应为零,而一阶矩恒为零,因此可以用消除量纲的三阶矩来度量偏度,对应组数据和非组数据的矩偏度系数为
矩偏度系数 = Error creating node with https://www.google.com/chart?cht=tx&chf=bg,s,FFFFFF00&chco=000000&chl=%5Cfrac%7B%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7D(x_%7Bi%7D%20-%20%5Cbar%20%7Bx%7D)%5E3%7D%7Bn-1%7D%7D%7B%5Cleft(%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7D(x_i%20-%20%5Cbar%7Bx%7D)%5E2%7D%7Bn-1%7D%5Cright)%5E3%7D. Unable to fetch: https://www.google.com/chart?cht=tx&chf=bg,s,FFFFFF00&chco=000000&chl=%5Cfrac%7B%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7D(x_%7Bi%7D%20-%20%5Cbar%20%7Bx%7D)%5E3%7D%7Bn-1%7D%7D%7B%5Cleft(%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7D(x_i%20-%20%5Cbar%7Bx%7D)%5E2%7D%7Bn-1%7D%5Cright)%5E3%7D --- Reason: Response code 404 (Not Found) --- Fetch details: { "attempt": 3, "method": "GET", "errorCode": "ERR_NON_2XX_3XX_RESPONSE", "responseStatusCode": 404, "responseStatusMessage": "Not Found", "requestHeaders": { "user-agent": "got (https://github.com/sindresorhus/got)", "accept-encoding": "gzip, deflate, br" }, "responseHeaders": { "date": "Tue, 23 Apr 2024 06:48:33 GMT", "content-type": "text/html", "server": "HTTP server (unknown)", "content-length": "49", "x-xss-protection": "0", "alt-svc": "h3=\":443\"; ma=2592000,h3-29=\":443\"; ma=2592000", "connection": "close" } } ---  和 Error creating node with https://www.google.com/chart?cht=tx&chf=bg,s,FFFFFF00&chco=000000&chl=%5Cfrac%7B%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7Df_i(x_i-%5Cbar%7Bx%7D)%5E3%7D%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7Df_i-1%7D%7D%7B%5Cleft%5B%20%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7Df_i(x_i-%5Cbar%7Bx%7D)%5E2%7D%7B%5Csum_%7Bx%3D1%7D%5E%7Bn%7Df_i-1%7D%20%5Cright%5D%5E3%20%7D. Unable to fetch: https://www.google.com/chart?cht=tx&chf=bg,s,FFFFFF00&chco=000000&chl=%5Cfrac%7B%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7Df_i(x_i-%5Cbar%7Bx%7D)%5E3%7D%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7Df_i-1%7D%7D%7B%5Cleft%5B%20%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7Df_i(x_i-%5Cbar%7Bx%7D)%5E2%7D%7B%5Csum_%7Bx%3D1%7D%5E%7Bn%7Df_i-1%7D%20%5Cright%5D%5E3%20%7D --- Reason: Response code 404 (Not Found) --- Fetch details: { "attempt": 3, "method": "GET", "errorCode": "ERR_NON_2XX_3XX_RESPONSE", "responseStatusCode": 404, "responseStatusMessage": "Not Found", "requestHeaders": { "user-agent": "got (https://github.com/sindresorhus/got)", "accept-encoding": "gzip, deflate, br" }, "responseHeaders": { "date": "Tue, 23 Apr 2024 06:48:37 GMT", "content-type": "text/html", "server": "HTTP server (unknown)", "content-length": "49", "x-xss-protection": "0", "alt-svc": "h3=\":443\"; ma=2592000,h3-29=\":443\"; ma=2592000", "connection": "close" } } ---

示例:

https://spreadsheets.google.com/pub?key=tj37eDmCFY8wamRCBj9y22A&gid=2